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authorLinus Torvalds <torvalds@linux-foundation.org>2022-03-25 02:19:43 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-25 02:19:43 +0300
commitb14ffae378aa1db993e62b01392e70d1e585fb23 (patch)
tree0ac179d24e8a62ec4c2732ed18d90d83da4b82d7 /Documentation/gpu/todo.rst
parent52deda9551a01879b3562e7b41748e85c591f14c (diff)
parentc6e90a1c660874736bd09c1fec6312b4b4c2ff7b (diff)
downloadlinux-b14ffae378aa1db993e62b01392e70d1e585fb23.tar.xz
Merge tag 'drm-next-2022-03-24' of git://anongit.freedesktop.org/drm/drm
Pull drm updates from Dave Airlie: "Lots of work all over, Intel improving DG2 support, amdkfd CRIU support, msm new hw support, and faster fbdev support. dma-buf: - rename dma-buf-map to iosys-map core: - move buddy allocator to core - add pci/platform init macros - improve EDID parser deep color handling - EDID timing type 7 support - add GPD Win Max quirk - add yes/no helpers to string_helpers - flatten syncobj chains - add nomodeset support to lots of drivers - improve fb-helper clipping support - add default property value interface fbdev: - improve fbdev ops speed ttm: - add a backpointer from ttm bo->ttm resource dp: - move displayport headers - add a dp helper module bridge: - anx7625 atomic support, HDCP support panel: - split out panel-lvds and lvds bindings - find panels in OF subnodes privacy: - add chromeos privacy screen support fb: - hot unplug fw fb on forced removal simpledrm: - request region instead of marking ioresource busy - add panel oreintation property udmabuf: - fix oops with 0 pages amdgpu: - power management code cleanup - Enable freesync video mode by default - RAS code cleanup - Improve VRAM access for debug using SDMA - SR-IOV rework special register access and fixes - profiling power state request ioctl - expose IP discovery via sysfs - Cyan skillfish updates - GC 10.3.7, SDMA 5.2.7, DCN 3.1.6 updates - expose benchmark tests via debugfs - add module param to disable XGMI for testing - GPU reset debugfs register dumping support amdkfd: - CRIU support - SDMA queue fixes radeon: - UVD suspend fix - iMac backlight fix i915: - minimal parallel submission for execlists - DG2-G12 subplatform added - DG2 programming workarounds - DG2 accelerated migration support - flat CCS and CCS engine support for XeHP - initial small BAR support - drop fake LMEM support - ADL-N PCH support - bigjoiner updates - introduce VMA resources and async unbinding - register definitions cleanups - multi-FBC refactoring - DG1 OPROM over SPI support - ADL-N platform enabling - opregion mailbox #5 support - DP MST ESI improvements - drm device based logging - async flip optimisation for DG2 - CPU arch abstraction fixes - improve GuC ADS init to work on aarch64 - tweak TTM LRU priority hint - GuC 69.0.3 support - remove short term execbuf pins nouveau: - higher DP/eDP bitrates - backlight fixes msm: - dpu + dp support for sc8180x - dp support for sm8350 - dpu + dsi support for qcm2290 - 10nm dsi phy tuning support - bridge support for dp encoder - gpu support for additional 7c3 SKUs ingenic: - HDMI support for JZ4780 - aux channel EDID support ast: - AST2600 support - add wide screen support - create DP/DVI connectors omapdrm: - fix implicit dma_buf fencing vc4: - add CSC + full range support - better display firmware handoff panfrost: - add initial dual-core GPU support stm: - new revision support - fb handover support mediatek: - transfer display binding document to yaml format. - add mt8195 display device binding. - allow commands to be sent during video mode. - add wait_for_event for crtc disable by cmdq. tegra: - YUV format support rcar-du: - LVDS support for M3-W+ (R8A77961) exynos: - BGR pixel format for FIMD device" * tag 'drm-next-2022-03-24' of git://anongit.freedesktop.org/drm/drm: (1529 commits) drm/i915/display: Do not re-enable PSR after it was marked as not reliable drm/i915/display: Fix HPD short pulse handling for eDP drm/amdgpu: Use drm_mode_copy() drm/radeon: Use drm_mode_copy() drm/amdgpu: Use ternary operator in `vcn_v1_0_start()` drm/amdgpu: Remove pointless on stack mode copies drm/amd/pm: fix indenting in __smu_cmn_reg_print_error() drm/amdgpu/dc: fix typos in comments drm/amdgpu: fix typos in comments drm/amd/pm: fix typos in comments drm/amdgpu: Add stolen reserved memory for MI25 SRIOV. drm/amdgpu: Merge get_reserved_allocation to get_vbios_allocations. drm/amdkfd: evict svm bo worker handle error drm/amdgpu/vcn: fix vcn ring test failure in igt reload test drm/amdgpu: only allow secure submission on rings which support that drm/amdgpu: fixed the warnings reported by kernel test robot drm/amd/display: 3.2.177 drm/amd/display: [FW Promotion] Release 0.0.108.0 drm/amd/display: Add save/restore PANEL_PWRSEQ_REF_DIV2 drm/amd/display: Wait for hubp read line for Pollock ...
Diffstat (limited to 'Documentation/gpu/todo.rst')
-rw-r--r--Documentation/gpu/todo.rst82
1 files changed, 61 insertions, 21 deletions
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index a1212b5b3026..127e76ee0b2d 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -222,7 +222,7 @@ Convert drivers to use drm_fbdev_generic_setup()
Most drivers can use drm_fbdev_generic_setup(). Driver have to implement
atomic modesetting and GEM vmap support. Historically, generic fbdev emulation
expected the framebuffer in system memory or system-like memory. By employing
-struct dma_buf_map, drivers with frambuffers in I/O memory can be supported
+struct iosys_map, drivers with frambuffers in I/O memory can be supported
as well.
Contact: Maintainer of the driver you plan to convert
@@ -234,13 +234,35 @@ Reimplement functions in drm_fbdev_fb_ops without fbdev
A number of callback functions in drm_fbdev_fb_ops could benefit from
being rewritten without dependencies on the fbdev module. Some of the
-helpers could further benefit from using struct dma_buf_map instead of
+helpers could further benefit from using struct iosys_map instead of
raw pointers.
Contact: Thomas Zimmermann <tzimmermann@suse.de>, Daniel Vetter
Level: Advanced
+Benchmark and optimize blitting and format-conversion function
+--------------------------------------------------------------
+
+Drawing to dispay memory quickly is crucial for many applications'
+performance.
+
+On at least x86-64, sys_imageblit() is significantly slower than
+cfb_imageblit(), even though both use the same blitting algorithm and
+the latter is written for I/O memory. It turns out that cfb_imageblit()
+uses movl instructions, while sys_imageblit apparently does not. This
+seems to be a problem with gcc's optimizer. DRM's format-conversion
+helpers might be subject to similar issues.
+
+Benchmark and optimize fbdev's sys_() helpers and DRM's format-conversion
+helpers. In cases that can be further optimized, maybe implement a different
+algorithm. For micro-optimizations, use movl/movq instructions explicitly.
+That might possibly require architecture-specific helpers (e.g., storel()
+storeq()).
+
+Contact: Thomas Zimmermann <tzimmermann@suse.de>
+
+Level: Intermediate
drm_framebuffer_funcs and drm_mode_config_funcs.fb_create cleanup
-----------------------------------------------------------------
@@ -410,19 +432,19 @@ Contact: Emil Velikov, respective driver maintainers
Level: Intermediate
-Use struct dma_buf_map throughout codebase
-------------------------------------------
+Use struct iosys_map throughout codebase
+----------------------------------------
-Pointers to shared device memory are stored in struct dma_buf_map. Each
+Pointers to shared device memory are stored in struct iosys_map. Each
instance knows whether it refers to system or I/O memory. Most of the DRM-wide
-interface have been converted to use struct dma_buf_map, but implementations
+interface have been converted to use struct iosys_map, but implementations
often still use raw pointers.
-The task is to use struct dma_buf_map where it makes sense.
+The task is to use struct iosys_map where it makes sense.
-* Memory managers should use struct dma_buf_map for dma-buf-imported buffers.
-* TTM might benefit from using struct dma_buf_map internally.
-* Framebuffer copying and blitting helpers should operate on struct dma_buf_map.
+* Memory managers should use struct iosys_map for dma-buf-imported buffers.
+* TTM might benefit from using struct iosys_map internally.
+* Framebuffer copying and blitting helpers should operate on struct iosys_map.
Contact: Thomas Zimmermann <tzimmermann@suse.de>, Christian König, Daniel Vetter
@@ -443,6 +465,21 @@ Contact: Thomas Zimmermann <tzimmermann@suse.de>
Level: Intermediate
+Request memory regions in all drivers
+-------------------------------------
+
+Go through all drivers and add code to request the memory regions that the
+driver uses. This requires adding calls to request_mem_region(),
+pci_request_region() or similar functions. Use helpers for managed cleanup
+where possible.
+
+Drivers are pretty bad at doing this and there used to be conflicts among
+DRM and fbdev drivers. Still, it's the correct thing to do.
+
+Contact: Thomas Zimmermann <tzimmermann@suse.de>
+
+Level: Starter
+
Core refactorings
=================
@@ -460,8 +497,12 @@ This is a really varied tasks with lots of little bits and pieces:
achieved by using an IPI to the local processor.
* There's a massive confusion of different panic handlers. DRM fbdev emulation
- helpers have one, but on top of that the fbcon code itself also has one. We
- need to make sure that they stop fighting over each another.
+ helpers had their own (long removed), but on top of that the fbcon code itself
+ also has one. We need to make sure that they stop fighting over each other.
+ This is worked around by checking ``oops_in_progress`` at various entry points
+ into the DRM fbdev emulation helpers. A much cleaner approach here would be to
+ switch fbcon to the `threaded printk support
+ <https://lwn.net/Articles/800946/>`_.
* ``drm_can_sleep()`` is a mess. It hides real bugs in normal operations and
isn't a full solution for panic paths. We need to make sure that it only
@@ -473,16 +514,15 @@ This is a really varied tasks with lots of little bits and pieces:
even spinlocks (because NMI and hardirq can panic too). We need to either
make sure to not call such paths, or trylock everything. Really tricky.
-* For the above locking troubles reasons it's pretty much impossible to
- attempt a synchronous modeset from panic handlers. The only thing we could
- try to achive is an atomic ``set_base`` of the primary plane, and hope that
- it shows up. Everything else probably needs to be delayed to some worker or
- something else which happens later on. Otherwise it just kills the box
- harder, prevent the panic from going out on e.g. netconsole.
+* A clean solution would be an entirely separate panic output support in KMS,
+ bypassing the current fbcon support. See `[PATCH v2 0/3] drm: Add panic handling
+ <https://lore.kernel.org/dri-devel/20190311174218.51899-1-noralf@tronnes.org/>`_.
-* There's also proposal for a simplied DRM console instead of the full-blown
- fbcon and DRM fbdev emulation. Any kind of panic handling tricks should
- obviously work for both console, in case we ever get kmslog merged.
+* Encoding the actual oops and preceding dmesg in a QR might help with the
+ dread "important stuff scrolled away" problem. See `[RFC][PATCH] Oops messages
+ transfer using QR codes
+ <https://lore.kernel.org/lkml/1446217392-11981-1-git-send-email-alexandru.murtaza@intel.com/>`_
+ for some example code that could be reused.
Contact: Daniel Vetter