[PATCH v1 0/4] drm/ast: Disable HW cursor when switching modes

[Thomas Zimmermann]

Should say [PATCH v2 0/4] instead

Am 05.08.20 um 12:54 schrieb Thomas Zimmermann:
> Since converting the ast driver to atomic modesettting, modesetting
> occationally locks up the graphics hardware and turns the display
> permanently dark. This happens once or twice per 10 mode switches.
> Investigation shows that the ast hardware presumably requires the HW
> cursor to be disabled while the modeswitch takes place.
> 
> This patchset fixes the problem by disabling planes before programming
> the CRTC mode or format. After the switch, the planes gets re-enabled if
> they were enabled before. For mere pageflip operations, nothing changes.
> 
> Patches #1 makes format changes work as intended: format registers are
> only updated if necessary. They used to be changed on each pageflip.
> Patch #2 puts the modesetting code before the plane-update code. This
> way, mode setting runs while planes are disabled. Patches #3 and #4
> add a commit-tail function that disables planes if the display's mode
> or format is going to change. The active planes will later get re-enabled
> by the plane-update handler.
> 
> Tested on AST2100 HW. The issue is not 100% reproducible, but does not
> show up after applying the patchset. I think the problem has been fixed.
> 
> v2:
> 	* rewrote the whole patchset
> 	* dropped the cursor patches
> 	* moved modesetting into atomic_begin()
> 	* disable planes in commit-tail function
> 	* don't require full modeset for format changes
> 
> Thomas Zimmermann (4):
>   drm/ast: Only set format registers if primary plane's format changes
>   drm/ast: Set display mode in atomic_begin()
>   drm/ast: Add commit-tail function
>   drm/ast: Disable planes while switching display modes
> 
>  drivers/gpu/drm/ast/ast_drv.h  |   2 +
>  drivers/gpu/drm/ast/ast_mode.c | 148 +++++++++++++++++++++++++--------
>  2 files changed, 114 insertions(+), 36 deletions(-)
> 
> --
> 2.28.0
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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