Documentation/gpu/todo.rst

11 ----------
29 Subsystem-wide refactorings
33 ---------------------------------------------
45 --------------------------------------------------
53 non-converted driver.  The "Atomic mode setting design overview" series [2]_
60   .. [1] https://blog.ffwll.ch/2014/11/atomic-modeset-support-for-kms-drivers.html
69 ---------------------------------------------------------
75 avoid confusion - the other helpers in that file are all deprecated legacy
83 ----------------------------------
88 - drm_plane_helper_funcs->atomic_check gets called for enabled or disabled
92   into the drm_plane_funcs->atomic_duplicate_state functions.
94 - Once that's done, helpers could stop calling ->atomic_check for disabled
97 - Then we could go through all the drivers and remove the more-or-less confused
98   checks for plane_state->fb and plane_state->crtc.
105 ----------------------------------------------------
108 nonblocking commits, and every driver had to hand-roll them. This is fixed
124 -----------------------
147 -----------------------
152 a bit too severe. So there's some follow-up work to adjust the function
159   drivers explicitly so that the legacy-on-atomic functions can use them.
176 Get rid of dev->struct_mutex from GEM drivers
177 ---------------------------------------------
179 ``dev->struct_mutex`` is the Big DRM Lock from legacy days and infested
189 For drivers that need ``struct_mutex`` it should be replaced with a driver-
193 performance-critical drivers it might also be better to go with a more
194 fine-grained per-buffer object and per-context lockings scheme. Currently only
202 ---------------------------------------------
204 Many drivers have their own per-object locking scheme, usually using
209 To solve this we need one standard per-object locking mechanism, which is
211 other driver specific per-object locks removed. The problem is that rolling out
218 ------------------------------------------------------------
224 those drivers back to using drm-formatted specific log messages.
227 sure your work will be merged - not everyone agrees that the DRM dmesg macros
235 ----------------------------------------------------
239 drm_mode_config_helper_suspend/resume(). Also there's still open-coded version
247 -------------------------------------------------------
258 Benchmark and optimize blitting and format-conversion function
259 --------------------------------------------------------------
264 On at least x86-64, sys_imageblit() is significantly slower than
268 seems to be a problem with gcc's optimizer. DRM's format-conversion
271 Benchmark and optimize fbdev's sys_() helpers and DRM's format-conversion
273 algorithm. For micro-optimizations, use movl/movq instructions explicitly.
274 That might possibly require architecture-specific helpers (e.g., storel()
282 -----------------------------------------------------------------
285 Various hold-ups:
287 - Need to switch over to the generic dirty tracking code using
290 - Need to switch to drm_fbdev_generic_setup(), otherwise a lot of the custom fb
293 - Need to switch to drm_gem_fb_create(), as now drm_gem_fb_create() checks for
296 - Many drivers subclass drm_framebuffer, we'd need a embedding compatible
305 ---------------------------
314 emulation. It would need to fully wrap the existing mmap ops, forwarding
315 everything after it has done the write-protect/mkwrite trickery:
317 - In the drm_fbdev_fb_mmap helper, if we need defio, change the
318   default page prots to write-protected with something like this::
320       vma->vm_page_prot = pgprot_wrprotect(vma->vm_page_prot);
322 - Set the mkwrite and fsync callbacks with similar implementions to the core
327 - Track the dirty pages in a separate structure (bitfield with one bit per page
337 -----------------------------------
339 - For most connectors it's a no-op to call drm_connector_register/unregister
343 - For dp drivers it's a bit more a mess, since we need the connector to be
351 ----------------------------
357 - Rework drivers to no longer use the load/unload callbacks, directly coding the
360 - Once all drivers are converted, remove the load/unload callbacks.
367 ---------------------------------------------------------------
369 Once EDID is parsed, the monitor HDMI support information is available through
381 --------------------------------------------
393 - audio (amdgpu, intel, gma500, radeon)
394 - brightness, contrast, etc (armada, nouveau) - overlay only (?)
395 - broadcast rgb (gma500, intel)
396 - colorkey (armada, nouveau, rcar) - overlay only (?)
397 - dither (amdgpu, nouveau, radeon) - varies across drivers
398 - underscan family (amdgpu, radeon, nouveau)
401 - colorspace (sti)
402 - tv format names, enhancements (gma500, intel)
403 - tv overscan, margins, etc. (gma500, intel)
404 - zorder (omapdrm) - same as zpos (?)
412 ----------------------------------------
415 instance knows whether it refers to system or I/O memory. Most of the DRM-wide
421 * Memory managers should use struct iosys_map for dma-buf-imported buffers.
430 --------------------------------------------------------------------------------------
445 -------------------------------------
460 ---------------------------------------
472 Remove disable/unprepare in remove/shutdown in panel-simple and panel-edp
473 -------------------------------------------------------------------------
477 double-calls prepare/enable/disable/unprepare. Eventually that should probably
481 drm_panel core when using panel-simple and panel-edp. Since those panel
492 calls to disable/unprepare in remove/shutdown in panel-simple and panel-edp
500 -------------------------------------------------
503 non-intuitive because, if there are errors, they return out of the *caller's*
522 ------------------------
533 * There's a massive confusion of different panic handlers. DRM fbdev emulation
537   into the DRM fbdev emulation helpers. A much cleaner approach here would be to
553   <https://lore.kernel.org/dri-devel/20190311174218.51899-1-noralf@tronnes.org/>`_.
558   <https://lore.kernel.org/lkml/1446217392-11981-1-git-send-email-alexandru.murtaza@intel.com/>`_
566 ----------------------------
570 - Convert drivers to support the drm_debugfs_add_files() function instead of
573 - Improve late-register debugfs by rolling out the same debugfs pre-register
577 - We probably want to have some support for debugfs files on crtc/connectors and
580   ->show() functions should obviously give you a pointer to the right object.
582 - The drm_driver->debugfs_init hooks we have is just an artifact of the old
587   this (together with the drm_minor->drm_device move) would allow us to remove
595 ---------------------
599 - Cleanup up the various ->destroy callbacks, which often are all the same
602 - Lots of drivers erroneously allocate DRM modeset objects using devm_kzalloc,
603   which results in use-after free issues on driver unload. This can be serious
615 Remove automatic page mapping from dma-buf importing
616 ----------------------------------------------------
618 When importing dma-bufs, the dma-buf and PRIME frameworks automatically map
626 buffer-sharing code. Fixing this is a bit more involved, since the import/export
640 --------------------------------------------------------------
642 The `KUnit <https://www.kernel.org/doc/html/latest/dev-tools/kunit/index.html>`_
646 A good candidate for the first unit tests are the format-conversion helpers in
654 ---------------------------------------------
671 ----------------------
677 Make KMS tests in i-g-t generic
678 -------------------------------
681 including tons of testcases for corner-cases in the modesetting API. It would
682 be awesome if those tests (at least the ones not relying on Intel-specific GEM
685 Basic work to run i-g-t tests on non-i915 is done, what's now missing is mass-
688 the non-i915 specific modeset tests.
693 ---------------------------------
702 ---------------------
720 ---------------------
736 - [v6,8/8] drm/client: Hack: Add bootsplash example
739 - [RFC PATCH v2 00/13] Kernel based bootsplash
740   https://lore.kernel.org/r/20171213194755.3409-1-mstaudt@suse.de
768    will need to be done to get the output <-> backlight device mapping
778 work. A possible solution here would be to pass a device and connector-name
817 Drivers that do per-buffer uploads, need a buffer damage handling (rather than
818 frame damage like drivers that do per-plane or per-CRTC uploads), but there is
822 framebuffer attached to a plane has changed since the last page-flip. Drivers
828 do per-buffer uploads.
841 ----------------------------
844 become obsolete, but some still provides good(-enough) framebuffers. The
850 existing hardware. The new driver's call-back functions are filled from
853 More complex fbdev drivers can be refactored step-by-step into a DRM