Drop issues already resolved in vkms: - CRC API Improvements to [1] add igt test to check extreme alpha values and [2] alpha blending; - [3] prime buffer sharing; - [4] writeback support; On the other hand, we also found or thought about other improvements since the last update of this document: - better support for IGT tests - improvements to writeback support - syzbot report Finally, we reorder items by the assumed complexity. [1] https://patchwork.freedesktop.org/series/55944/ [2] https://patchwork.freedesktop.org/series/80823/ [3] https://patchwork.freedesktop.org/series/63212/ [4] https://patchwork.freedesktop.org/series/81177/ Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Rodrigo Siqueira <rodrigosiqueiramelo@xxxxxxxxx> Cc: Haneen Mohammed <hamohammed.sa@xxxxxxxxx> Signed-off-by: Melissa Wen <melissa.srw@xxxxxxxxx> --- Documentation/gpu/vkms.rst | 99 ++++++++++++++++++++------------------ 1 file changed, 53 insertions(+), 46 deletions(-) diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst index 61586fc861bb..82a01bb4104c 100644 --- a/Documentation/gpu/vkms.rst +++ b/Documentation/gpu/vkms.rst @@ -10,36 +10,24 @@ TODO ==== -CRC API Improvements --------------------- - -- Optimize CRC computation ``compute_crc()`` and plane blending ``blend()`` - -- Use the alpha value to blend vaddr_src with vaddr_dst instead of - overwriting it in ``blend()``. - -- Add igt test to check cleared alpha value for XRGB plane format. - -- Add igt test to check extreme alpha values i.e. fully opaque and fully - transparent (intermediate values are affected by hw-specific rounding modes). - -Runtime Configuration ---------------------- - -We want to be able to reconfigure vkms instance without having to reload the -module. Use/Test-cases: - -- Hotplug/hotremove connectors on the fly (to be able to test DP MST handling of - compositors). +If you want to do any of the items listed below, please share your interest +with one of the VKMS maintainers. -- Configure planes/crtcs/connectors (we'd need some code to have more than 1 of - them first). +IGT better support +------------------ -- Change output configuration: Plug/unplug screens, change EDID, allow changing - the refresh rate. +- Investigate: (1) test cases on kms_plane that are failing due to timeout on + capturing CRC; (2) when running kms_flip test cases in sequence, some + successful individual test cases are failing randomly. -The currently proposed solution is to expose vkms configuration through -configfs. All existing module options should be supported through configfs too. +- VKMS already has support for vblanks simulated via hrtimers, which can be + tested with kms_flip test; in some way, we can say that VKMS already mimics + the real hardware vblank. However, we also have virtual hardware that does + not support vblank interrupt and completes page_flip events right away; in + this case, compositor developers may end up creating a busy loop on virtual + hardware. It would be useful to support Virtual Hardware behavior in VKMS + because this can help compositor developers to test their features in + multiple scenarios. Add Plane Features ------------------ @@ -55,34 +43,50 @@ There's lots of plane features we could add support for: - Additional buffer formats, especially YUV formats for video like NV12. Low/high bpp RGB formats would also be interesting. -- Async updates (currently only possible on cursor plane using the legacy cursor - api). +- Async updates (currently only possible on cursor plane using the legacy + cursor api). + +For all of these, we also want to review the igt test coverage and make sure +all relevant igt testcases work on vkms. + +Prime Buffer Sharing +-------------------- -For all of these, we also want to review the igt test coverage and make sure all -relevant igt testcases work on vkms. +- Syzbot report: + WARNING in vkms_gem_free_object: https://lkml.org/lkml/2019/10/13/220 + +Runtime Configuration +--------------------- + +We want to be able to reconfigure vkms instance without having to reload the +module. Use/Test-cases: + +- Hotplug/hotremove connectors on the fly (to be able to test DP MST handling + of compositors). + +- Configure planes/crtcs/connectors (we'd need some code to have more than 1 of + them first). + +- Change output configuration: Plug/unplug screens, change EDID, allow changing + the refresh rate. + +The currently proposed solution is to expose vkms configuration through +configfs. All existing module options should be supported through configfs +too. Writeback support ----------------- -Currently vkms only computes a CRC for each frame. Once we have additional plane -features, we could write back the entire composited frame, and expose it as: +- The writeback and CRC capture operations share the use of composer_enabled + boolean to ensure vblanks. Probably, when these operations work together, + composer_enabled needs to refcounting the composer state to proper work. -- Writeback connector. This is useful for testing compositors if you don't have - hardware with writeback support. +- Add support for cloned writeback outputs and related test cases using a + cloned output in the IGT kms_writeback. - As a v4l device. This is useful for debugging compositors on special vkms configurations, so that developers see what's really going on. -Prime Buffer Sharing --------------------- - -We already have vgem, which is a gem driver for testing rendering, similar to -how vkms is for testing the modeset side. Adding buffer sharing support to vkms -allows us to test them together, to test synchronization and lots of other -features. Also, this allows compositors to test whether they work correctly on -SoC chips, where the display and rendering is very often split between 2 -drivers. - Output Features --------------- @@ -93,7 +97,10 @@ Output Features - Add support for link status, so that compositors can validate their runtime fallbacks when e.g. a Display Port link goes bad. -- All the hotplug handling describe under "Runtime Configuration". +CRC API Improvements +-------------------- + +- Optimize CRC computation ``compute_crc()`` and plane blending ``blend()`` Atomic Check using eBPF ----------------------- -- 2.28.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
