Affected versions
Firefox Nightly 80.0a1

Affected platforms

Windows 10 x64

Preconditions

gfx.webrender.all = true or gfx.webrender.all = false
apz.allow_zooming = true
apz.windows.use_direct_manipulation = true

Steps to reproduce

1. Navigate to any website (e.g twitch.com)
2. Zoom in/Zoom out using a touchpad

Expected result

Pages should be correctly displayed while pinch zooming in/zooming out many times on any website

Actual Result

Pages are not correctly displayed while pinch zooming in/zooming out many times on any website

Notes

The issue isn't reproducible on chrome

How long does the issue last? Does it stay like the screenshot for a long time or just flash like that for half a second?

I couldn't reproduce beyond the usual very temporary checkerboarding we get on zooming.

The issue stays for a second or less, it could be more visible while pinch zooming in/zooming out repeatedly on any website. The same action comparing to google chrome shows lake of responsiveness.

S3 given this sounds like transient checkerboarding.

I'm seeing this issue also on the latest Nightly 81.0a1 and Mac OS X 10.15 a (with the same preference settings as the one from the Description).

@Hani: Could you attach about:support?

Application Basics

Name: Firefox
Version: 82.0a1
Build ID: 20200903151816
Distribution ID:
Update Channel: nightly
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:82.0) Gecko/20100101 Firefox/82.0
OS: Windows_NT 10.0 18363
Launcher Process: Enabled
Multiprocess Windows: 1/1 Enabled by default
Remote Processes: 4
Enterprise Policies: Inactive
Google Location Service Key: Found
Google Safebrowsing Key: Found
Mozilla Location Service Key: Found
Safe Mode: false

Crash Reports for the Last 3 Days

Nightly Features

Name: DoH Roll-Out
Version: 2.0.0
ID: doh-rollout@mozilla.org

Name: Firefox Screenshots
Version: 39.0.0
ID: screenshots@mozilla.org

Name: Form Autofill
Version: 1.0
ID: formautofill@mozilla.org

Name: Web Compat
Version: 14.0.0
ID: webcompat@mozilla.org

Name: WebCompat Reporter
Version: 1.4.0
ID: webcompat-reporter@mozilla.org

Remote Processes

Type: Web Content
Count: 1 / 8

Type: Extension
Count: 1

Type: GPU
Count: 1

Type: Socket
Count: 1

Add-ons

Name: Amazon.com
Type: extension
Version: 1.3
Enabled: true
ID: amazondotcom@search.mozilla.org

Name: Bing
Type: extension
Version: 1.2
Enabled: true
ID: bing@search.mozilla.org

Name: DuckDuckGo
Type: extension
Version: 1.1
Enabled: true
ID: ddg@search.mozilla.org

Name: Google
Type: extension
Version: 1.1
Enabled: true
ID: google@search.mozilla.org

Name: Wikipedia (en)
Type: extension
Version: 1.1
Enabled: true
ID: wikipedia@search.mozilla.org

Security Software

Type: Cisco AMP for Endpoints

Type:

Type: Windows Firewall

Graphics

Features
Compositing: WebRender
Asynchronous Pan/Zoom: wheel input enabled; scrollbar drag enabled; keyboard enabled; autoscroll enabled; smooth pinch-zoom enabled
WebGL 1 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000010264) EGL_VERSION: 1.4 (ANGLE 2.1.0.6c72b64f910d) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_CHROMIUM_sync_control EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_ANGLE_robust_resource_initialization EGL_ANGLE_create_context_extensions_enabled EGL_ANDROID_blob_cache EGL_ANDROID_recordable EGL_ANGLE_image_d3d11_texture EGL_ANGLE_create_context_backwards_compatible EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses EGL_KHR_debug EGL_ANGLE_explicit_context EGL_ANGLE_feature_control IsWebglOutOfProcessEnabled: 0
WebGL 1 Driver Renderer: Google Inc. -- ANGLE (Intel(R) UHD Graphics 630 Direct3D11 vs_5_0 ps_5_0)
WebGL 1 Driver Version: OpenGL ES 2.0.0 (ANGLE 2.1.0.6c72b64f910d)
WebGL 1 Driver Extensions: GL_ANGLE_client_arrays GL_ANGLE_depth_texture GL_ANGLE_explicit_context GL_ANGLE_explicit_context_gles1 GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_memory_size GL_ANGLE_multi_draw GL_ANGLE_multiview_multisample GL_ANGLE_pack_reverse_row_order GL_ANGLE_program_cache_control GL_ANGLE_provoking_vertex GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_lose_context GL_CHROMIUM_sync_query GL_EXT_blend_func_extended GL_EXT_blend_minmax GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_float_blend GL_EXT_frag_depth GL_EXT_instanced_arrays GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_bptc GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_s3tc_srgb GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_KHR_parallel_shader_compile GL_KHR_robust_buffer_access_behavior GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_depth24 GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_surfaceless_context GL_OES_texture_3D GL_OES_texture_border_clamp GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_array_object OES_compressed_EAC_R11_signed_texture OES_compressed_EAC_R11_unsigned_texture OES_compressed_EAC_RG11_signed_texture OES_compressed_EAC_RG11_unsigned_texture OES_compressed_ETC2_RGB8_texture OES_compressed_ETC2_RGBA8_texture OES_compressed_ETC2_punchthroughA_RGBA8_texture OES_compressed_ETC2_punchthroughA_sRGB8_alpha_texture OES_compressed_ETC2_sRGB8_alpha8_texture OES_compressed_ETC2_sRGB8_texture
WebGL 1 Extensions: ANGLE_instanced_arrays EXT_blend_minmax EXT_color_buffer_half_float EXT_float_blend EXT_frag_depth EXT_shader_texture_lod EXT_sRGB EXT_texture_compression_bptc EXT_texture_filter_anisotropic MOZ_debug OES_element_index_uint OES_standard_derivatives OES_texture_float OES_texture_float_linear OES_texture_half_float OES_texture_half_float_linear OES_vertex_array_object WEBGL_color_buffer_float WEBGL_compressed_texture_s3tc WEBGL_compressed_texture_s3tc_srgb WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_depth_texture WEBGL_draw_buffers WEBGL_lose_context
WebGL 2 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000010264) EGL_VERSION: 1.4 (ANGLE 2.1.0.6c72b64f910d) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_CHROMIUM_sync_control EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_ANGLE_robust_resource_initialization EGL_ANGLE_create_context_extensions_enabled EGL_ANDROID_blob_cache EGL_ANDROID_recordable EGL_ANGLE_image_d3d11_texture EGL_ANGLE_create_context_backwards_compatible EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses EGL_KHR_debug EGL_ANGLE_explicit_context EGL_ANGLE_feature_control IsWebglOutOfProcessEnabled: 0
WebGL 2 Driver Renderer: Google Inc. -- ANGLE (Intel(R) UHD Graphics 630 Direct3D11 vs_5_0 ps_5_0)
WebGL 2 Driver Version: OpenGL ES 3.0.0 (ANGLE 2.1.0.6c72b64f910d)
WebGL 2 Driver Extensions: GL_ANGLE_client_arrays GL_ANGLE_copy_texture_3d GL_ANGLE_depth_texture GL_ANGLE_explicit_context GL_ANGLE_explicit_context_gles1 GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_memory_size GL_ANGLE_multi_draw GL_ANGLE_multiview_multisample GL_ANGLE_pack_reverse_row_order GL_ANGLE_program_cache_control GL_ANGLE_provoking_vertex GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_multisample GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_lose_context GL_CHROMIUM_sync_query GL_EXT_blend_func_extended GL_EXT_blend_minmax GL_EXT_color_buffer_float GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_float_blend GL_EXT_frag_depth GL_EXT_instanced_arrays GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_bptc GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_s3tc_srgb GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_norm16 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_KHR_parallel_shader_compile GL_KHR_robust_buffer_access_behavior GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_EGL_image_external_essl3 GL_OES_depth24 GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_surfaceless_context GL_OES_texture_3D GL_OES_texture_border_clamp GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_array_object GL_OVR_multiview GL_OVR_multiview2 OES_compressed_EAC_R11_signed_texture OES_compressed_EAC_R11_unsigned_texture OES_compressed_EAC_RG11_signed_texture OES_compressed_EAC_RG11_unsigned_texture OES_compressed_ETC2_RGB8_texture OES_compressed_ETC2_RGBA8_texture OES_compressed_ETC2_punchthroughA_RGBA8_texture OES_compressed_ETC2_punchthroughA_sRGB8_alpha_texture OES_compressed_ETC2_sRGB8_alpha8_texture OES_compressed_ETC2_sRGB8_texture
WebGL 2 Extensions: EXT_color_buffer_float EXT_float_blend EXT_texture_compression_bptc EXT_texture_filter_anisotropic MOZ_debug OES_texture_float_linear OVR_multiview2 WEBGL_compressed_texture_s3tc WEBGL_compressed_texture_s3tc_srgb WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_lose_context
Direct2D: true
Uses Tiling (Content): true
Off Main Thread Painting Enabled: true
Off Main Thread Painting Worker Count: 4
Target Frame Rate: 60
DirectWrite: true (10.0.18362.836)
GPU #1
Active: Yes
Description: Intel(R) UHD Graphics 630
Vendor ID: 0x8086
Device ID: 0x3e9b
Driver Version: 26.20.100.7262
Driver Date: 9-25-2019
Drivers: igdumdim64 igd10iumd64 igd10iumd64 igd12umd64 igdumdim32 igd10iumd32 igd10iumd32 igd12umd32
Subsys ID: 08ea1028
RAM: 0
GPU #2
Active: No
Description: NVIDIA GeForce GTX 1650
Vendor ID: 0x10de
Device ID: 0x1f91
Driver Version: 26.21.14.4145
Driver Date: 11-26-2019
Drivers: C:\Windows\System32\DriverStore\FileRepository\nvdm.inf_amd64_fe99e42491776c29\nvldumdx.dll,C:\Windows\System32\DriverStore\FileRepository\nvdm.inf_amd64_fe99e42491776c29\nvldumdx.dll,C:\Windows\System32\DriverStore\FileRepository\nvdm.inf_amd64_fe99e42491776c29\nvldumdx.dll,C:\Windows\System32\DriverStore\FileRepository\nvdm.inf_amd64_fe99e42491776c29\nvldumdx.dll C:\Windows\System32\DriverStore\FileRepository\nvdm.inf_amd64_fe99e42491776c29\nvldumd.dll,C:\Windows\System32\DriverStore\FileRepository\nvdm.inf_amd64_fe99e42491776c29\nvldumd.dll,C:\Windows\System32\DriverStore\FileRepository\nvdm.inf_amd64_fe99e42491776c29\nvldumd.dll,C:\Windows\System32\DriverStore\FileRepository\nvdm.inf_amd64_fe99e42491776c29\nvldumd.dll
Subsys ID: 08ea1028
RAM: 4096
Diagnostics
AzureCanvasBackend: direct2d 1.1
AzureCanvasBackend (UI Process): skia
AzureContentBackend: skia
AzureContentBackend (UI Process): skia
AzureFallbackCanvasBackend (UI Process): none
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Display0: 1920x1080@60Hz
DisplayCount: 1
GPUProcessPid: 1468
GPUProcess: Terminate GPU Process
Device Reset: Trigger Device Reset
ClearType Parameters: Gamma: 1.8 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 50
Decision Log
HW_COMPOSITING:
available by default
D3D11_COMPOSITING:
available by default
DIRECT2D:
available by default
D3D11_HW_ANGLE:
available by default
GPU_PROCESS:
available by default
WEBRENDER:
opt-in by default: WebRender is an opt-in feature
available by user: Qualified enabled by pref
WEBRENDER_QUALIFIED:
available by default
WEBRENDER_COMPOSITOR:
available by default
WEBRENDER_PARTIAL:
available by default
WEBRENDER_ANGLE:
opt-in by default: WebRender ANGLE is an opt-in feature
available by user: Enabled
WEBRENDER_DCOMP_PRESENT:
opt-in by default: WebRender DirectComposition is an opt-in feature
available by user: Enabled
OMTP:
available by default
ADVANCED_LAYERS:
available by default
blocked by env: Blocked from fallback candidate by WebRender usage
WEBGPU:
disabled by default: Disabled by default

Media

Audio Backend: wasapi
Max Channels: 2
Preferred Sample Rate: 48000
Roundtrip latency (standard deviation): ...
Output Devices
Name: Group
Speakers/Headphones (3- Realtek(R) Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0236&SUBSYS_102808EA&REV_1000\4&210eeee4&0&0001
PHILIPS FTV (2- NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0094&SUBSYS_10280000&REV_1001\5&2bc98670&0&0001
Digital Audio (HDMI) (2- High Definition Audio Device): HDAUDIO\FUNC_01&VEN_10DE&DEV_0094&SUBSYS_10280000&REV_1001\5&2bc98670&0&0001
Headphones (3- Realtek(R) Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0236&SUBSYS_102808EA&REV_1000\4&210eeee4&0&0001
Input Devices
Name: Group
Stereo Mix (3- Realtek(R) Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0236&SUBSYS_102808EA&REV_1000\4&210eeee4&0&0001
Microphone (3- Realtek(R) Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0236&SUBSYS_102808EA&REV_1000\4&210eeee4&0&0001
Microphone (3- Realtek(R) Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0236&SUBSYS_102808EA&REV_1000\4&210eeee4&0&0001
Internal AUX Jack (3- Realtek(R) Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0236&SUBSYS_102808EA&REV_1000\4&210eeee4&0&0001
Internal AUX Jack (High Definition Audio Device): HDAUDIO\FUNC_01&VEN_8086&DEV_280B&SUBSYS_80860101&REV_1000\4&210eeee4&0&0201
Internal AUX Jack (2- High Definition Audio Device): HDAUDIO\FUNC_01&VEN_10DE&DEV_0094&SUBSYS_10280000&REV_1001\5&2bc98670&0&0001
Internal AUX Jack (2- NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0094&SUBSYS_10280000&REV_1001\5&2bc98670&0&0001
Media Capabilities
Enumerate database

Environment Variables

MOZ_APP_RESTART: 1
MOZ_CRASHREPORTER_DATA_DIRECTORY: C:\Users\hani.yacoub\AppData\Roaming\Mozilla\Firefox\Crash Reports
MOZ_CRASHREPORTER_EVENTS_DIRECTORY: C:\Users\hani.yacoub\AppData\Roaming\Mozilla\Firefox\Crash Reports\events
MOZ_CRASHREPORTER_PING_DIRECTORY: C:\Users\hani.yacoub\AppData\Roaming\Mozilla\Firefox\Pending Pings
MOZ_CRASHREPORTER_RESTART_ARG_0: C:\Users\hani.yacoub\Desktop\Nightly\firefox.exe
MOZ_CRASHREPORTER_RESTART_ARG_2: -no-remote
MOZ_CRASHREPORTER_STRINGS_OVERRIDE: C:\Users\hani.yacoub\Desktop\Nightly\browser\crashreporter-override.ini
MOZ_NO_REMOTE: 1

Experimental Features

about:home startup cache (browser.startup.homepage.abouthome_cache.enabled): false
Cookies: SameSite=Lax by default (network.cookie.sameSite.laxByDefault): true
Cookies: SameSite=None requires secure attribute (network.cookie.sameSite.noneRequiresSecure): true
Cookies: Schemeful SameSite (network.cookie.sameSite.schemeful): true
CSS: Constructable Stylesheets (layout.css.constructable-stylesheets.enabled): false
CSS: Pseudo-class: :focus-visible (layout.css.focus-visible.enabled): true
CSS: Masonry Layout (layout.css.grid-template-masonry-value.enabled): false
Developer Tools: Color Scheme Simulation (devtools.inspector.color-scheme-simulation.enabled): false
Developer Tools: Compatibility Panel (devtools.inspector.compatibility.enabled): true
Developer Tools: Execution Context Selector (devtools.webconsole.input.context): true
Developer Tools: Service Worker debugging (devtools.debugger.features.windowless-service-workers): false
Graphics: Smooth Pinch Zoom (apz.allow_zooming): true
Media: AVIF (image.avif.enabled): false
Web API: Media Session API (dom.media.mediasession.enabled): true
Print Preview Redesign (print.tab_modal.enabled): true
Web API: beforeinput Event (dom.input_events.beforeinput.enabled): false
Web API: inputmode (dom.forms.inputmode): true
Web API: <link rel="preload"> (network.preload): true
Web API: WebGPU (dom.webgpu.enabled): false

Important Modified Preferences

browser.cache.disk.amount_written: 14613
browser.cache.disk.filesystem_reported: 1
browser.contentblocking.category: standard
browser.search.region: RO
browser.startup.homepage_override.buildID: 20200903151816
browser.startup.homepage_override.mstone: 82.0a1
browser.urlbar.placeholderName: Google
dom.push.userAgentID: 740475df3bb0430bbd60a3ce46eb2c84
extensions.lastAppVersion: 82.0a1
gfx.crash-guard.status.wmfvpxvideo: 2
gfx.crash-guard.wmfvpxvideo.appVersion: 82.0a1
gfx.crash-guard.wmfvpxvideo.deviceID: 0x3e9b
gfx.crash-guard.wmfvpxvideo.driverVersion: 26.20.100.7262
layers.mlgpu.sanity-test-failed: true
media.gmp-gmpopenh264.abi: x86_64-msvc-x64
media.gmp-gmpopenh264.lastUpdate: 1599205791
media.gmp-gmpopenh264.version: 1.8.1.1
media.gmp-manager.buildID: 20200827212940
media.gmp-manager.lastCheck: 1599205791
media.gmp-widevinecdm.abi: x86_64-msvc-x64
media.gmp-widevinecdm.lastUpdate: 1599205793
media.gmp-widevinecdm.version: 4.10.1582.2
media.gmp.storage.version.observed: 1
media.hardware-video-decoding.failed: false
network.trr.blocklist_cleanup_done: true
places.history.expiration.transient_current_max_pages: 112348
privacy.sanitize.pending: [{"id":"newtab-container","itemsToClear":[],"options":{}}]
security.remote_settings.crlite_filters.checked: 1599205789
security.remote_settings.intermediates.checked: 1599205789
security.sandbox.content.tempDirSuffix: {af93ec3e-bdb7-463a-bb87-3dc7f316fde2}
security.sandbox.plugin.tempDirSuffix: {5269dec1-9e41-4be2-9117-96a370559c91}
signon.usage.hasEntry: false
ui.osk.debug.keyboardDisplayReason: IKPOS: Touch screen not found.

Important Locked Preferences

Places Database

Accessibility

Activated: false
Prevent Accessibility: 0
Accessible Handler Used: false
Accessibility Instantiator:

Library Versions

NSPR
Expected minimum version: 4.29 Beta
Version in use: 4.29 Beta

NSS
Expected minimum version: 3.57 Beta
Version in use: 3.57 Beta

NSSSMIME
Expected minimum version: 3.57 Beta
Version in use: 3.57 Beta

NSSSSL
Expected minimum version: 3.57 Beta
Version in use: 3.57 Beta

NSSUTIL
Expected minimum version: 3.57 Beta
Version in use: 3.57 Beta

Sandbox

Content Process Sandbox Level: 6
Effective Content Process Sandbox Level: 6

Startup Cache

Disk Cache Path: C:\Users\hani.yacoub\AppData\Local\Mozilla\Firefox\Profiles\0oy4s85h.fry\startupCache\startupCache.8.little
Ignore Disk Cache: false
Found Disk Cache on Init: false
Wrote to Disk Cache: false

Internationalization & Localization

Application Settings
Requested Locales: ["en-US"]
Available Locales: ["en-US"]
App Locales: ["en-US"]
Regional Preferences: ["en-US"]
Default Locale: "en-US"
Operating System
System Locales: ["en-US"]
Regional Preferences: ["en-US"]

Remote Debugging (Chromium Protocol)

Accepting Connections: false
URL:

This checkerboarding is more visible when WebRender is off (by setting the pref Gfx.webrender.force-disabled = true) - tested On Nightly 82.0a1 and Mac OS X 10.15.

Checkerboarding is even more easy to reproduce on websites with a darker background. Please see the video for more details: https://imgur.com/a/2ui2ONW

I wrote a WIP that tries to detect during the OnScale function if APZ is close to checkerboarding. If it is, then it triggers a repaint request immediately. This seems to improve things, more so with WR than not, as I would expect. With layers doing the paint at the new resolution is still expensive and so that takes time, and we checkerboard in the meantime. I think if we want to improve it further we'll want to increase the displayport width in this scenario so that the main thread can do a better job of painting the area that will be composited. I'll give that a shot too.

https://treeherder.mozilla.org/#/jobs?repo=try&group_state=expanded&revision=de32fdbedc8c6707f901afe4860d75ac8aef9532 with one set of patches that seem to help some by triggering repaints more frequently.

https://treeherder.mozilla.org/#/jobs?repo=try&group_state=expanded&revision=56a331310915a1820418a4bb81cd2783261ce587 has an additional patch to change the shape of the displayport while zooming so that it is less likely to checkerboard horizontally while zooming out.

No functional changes to the code, just some variable renaming and logging
removal.

Depends on D93797

Our existing displayport calculation heuristics generally favour a more vertical
displayport because that's the direction most scrolling occurs in. However, when
zooming, we actually want to try and preserve the aspect ratio of the composition
size, because zooming is an operation that scales the content equally on both
axes and favouring the y-axis in the displayport can result in more checkerboarding
on the x-axis.

Depends on D93798

New try push is at https://treeherder.mozilla.org/#/jobs?repo=try&revision=b01a75af563169c3046674e548200b46623ba968 but is running into unrelated zstd corruption errors on some builds.

As I've only tested these patches on top of the patches from bug 1671284 I'll wait until those land before landing these.

https://hg.mozilla.org/mozilla-central/rev/f132844034e9
https://hg.mozilla.org/mozilla-central/rev/e891a2f479f0
https://hg.mozilla.org/mozilla-central/rev/b6b521c2e152

Comment on attachment 9182040 [details]
Bug 1654290 - When zooming, change the displayport shape to match the composition size. r?botond

Beta/Release Uplift Approval Request

• User impact if declined: When pinch-zooming out, there are somewhat frequent instances of checkerboarding. The checkerboarding is transient and goes away by itself after the browser does another repaint, but these patches help to reduce the duration and amount of checkerboarding which improves the user experience.
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: Go to some heavy sites and pinch zoom in and out. The patches in this bug should reduce the severity of checkerboarding, although doesn't get rid of it completely.
• List of other uplifts needed: Bug 1671284
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Patches are fairly low risk, although it would be better to uplift this after bug 1671284 has been uplifted. If we uplift this first, it may make that bug trigger more often.
• String changes made/needed: none

Verified as fixed on Firefox Nightly 84.0a1 (2020-10-20) on Windows 10 x64 and MacOS 10.15 on both touchpad and touchscreen with gfx.webrender.all = true.

However, on MacOS 10.15 with "gfx.webrender.all = false" pinch zooming is less smother than setting gfx.webrender.all = true.
Please see the video comparing Firefox Nightly with gfx.webrender.all = true (on the left) and a Firefox Nightly with gfx.webrender.all = true (on the right). This difference is not visible on Windows 10.
Is this expected or should we log a separate bug for this case?
Thanks.

Note that macOS nightly will have webrender enabled regardless of what you set to gfx.webrender.all to. Please check about:support for whether or not Webrender is actually enabled. If you want to forcibly disable webrender you need to set gfx.webrender.force-disabled=true.

My bad here. Webrender was disabled by setting "gfx.webrender.force-disabled=true" and in about:support "Compositing" is OpenGL.
Attaching the video I mentioned in previous comment: https://imgur.com/a/yfuOZiO
On the left is a Firefox Nightly with Webrender ON and on the right is a Firefox Nightly with Webrender OFF.

Thanks! Looking at the video, I do see the performance is better with WebRender on. However we are planning to turn WR on by default on macOS in 84 release anyway, so I don't think it's worth spending the time to investigate the relatively minor performance issue in the non-WR configuration. It would take some effort and the patch would have to be uplifted to 83 and would only help on that one release, so I think it's fine to leave it as-is.

Verified as fixed on Firefox 83.0b3 on Windows 10 x64 and MacOS 10.15 on both touchpad and touchscreen.

Comment on attachment 9182040 [details]
Bug 1654290 - When zooming, change the displayport shape to match the composition size. r?botond

Approved for beta 4 alongside bug 1672077

Looks like this bug was marked verified on 83 even though it was never uplifted there. It still needs uplifting.

This'll be uplifted for beta 6 at this point.

I don't know why I thought this was uplifted, but the issue wasn't reproducible on Firefox 83.0b3 on Windows 10 x64 and MacOS 10.15.
I will double check on Firefox 83.0b6 when it's going to be available and compare it with Firefox 83.0b3 to see if there are any differences.

https://hg.mozilla.org/releases/mozilla-beta/rev/b60f4498a75a
https://hg.mozilla.org/releases/mozilla-beta/rev/3f7578589539
https://hg.mozilla.org/releases/mozilla-beta/rev/1a0d56318769

I compared both Firefox 83.0b3 and Firefox 83.0b6 on Windows 10 x64 and on MacOS 10.15, even though on Firefox 83.0b3 is noticed that pinch zooming is smoother comparing with a build from when this bug was logged, but on Firefox 83.0b6 the smoothness is more visible and not even a small glitch is observed.
Verified as fixed on Firefox 83.0b6 on Windows 10 x64 both touchscreen and touchpad and on MacOS 10.15 using a touchpad.

Great, thanks!