Merge tag 'drm-misc-next-2022-03-03' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

drm-misc-next for v5.18:

UAPI Changes:

Cross-subsystem Changes:
- Improve performance of some fbdev ops, in some cases up to 6x faster.

Core Changes:
- Some small DP fixes.
- Find panels in subnodes of OF devices, and add of_get_drm_panel_display_mode
  to retrieve mode.
- Add drm_object_property_get_default_value and use it for resetting
  zpos in plane state reset, removing the need for individual drivers
  to do it.
- Same for color encoding and color range props.
- Update panic handling todo doc.
- Add todo that format conversion helpers should be sped up similarly to fbdev ops.

Driver Changes:
- Add panel orientation property to simpledrm for quirked panels.
- Assorted small fixes to tiny/repaper, nouveau, stm, omap, ssd130x.
- Add crc support to stm/ltdc.
- Add MIPI DBI compatible SPI driver
- Assorted small fixes to tiny panels and bridge drivers.
- Add AST2600 support to aspeed.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/48fabd78-ade9-f80b-c724-13726c7be69e@linux.intel.com

1 files changed, 36 insertions, 11 deletions

diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 7bf7f2111696..127e76ee0b2d 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -241,6 +241,28 @@ 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
 -----------------------------------------------------------------
@@ -475,8 +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
@@ -488,16 +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