[Nouveau] [PATCH] drm/nouveau/kms/nve4-nv108: Limit cursors to 128x128

[Roy Spliet]

Tested-by: Roy Spliet <nouveau at spliet.org>

Op 08-03-2021 om 16:50 schreef Daniel Thompson:
> On Thu, Mar 04, 2021 at 08:52:41PM -0500, Lyude Paul wrote:
>> While Kepler does technically support 256x256 cursors, it turns out that
>> Kepler actually has some additional requirements for scanout surfaces that
>> we're not enforcing correctly, which aren't present on Maxwell and later.
>> Cursor surfaces must always use small pages (4K), and overlay surfaces must
>> always use large pages (128K).
>>
>> Fixing this correctly though will take a bit more work: as we'll need to
>> add some code in prepare_fb() to move cursor FBs in large pages to small
>> pages, and vice-versa for overlay FBs. So until we have the time to do
>> that, just limit cursor surfaces to 128x128 - a size small enough to always
>> default to small pages.
>>
>> This means small ovlys are still broken on Kepler, but it is extremely
>> unlikely anyone cares about those anyway :).
>>
>> Signed-off-by: Lyude Paul <lyude at redhat.com>
>> Fixes: d3b2f0f7921c ("drm/nouveau/kms/nv50-: Report max cursor size to userspace")
>> Cc: <stable at vger.kernel.org> # v5.11+
> 
> I was experiencing problems with the mouse cursor on my system in v5.11
> and after a bisect to help me search the web I found my way to this
> patch, which fixed the problem for me.
> 
> Mine is an Armv8 system but there is nothing particularly exotic from a
> graphics card or software point of view: Debian bullseye/wayland
> (gnome-shell 3.38.3, mesa-20.3.4) running on a GT-710.
> 
> However FWIW:
> Tested-by: Daniel Thompson <daniel.thompson at linaro.org>
> 
> 
> Daniel.
> 
> 
>> ---
>>   drivers/gpu/drm/nouveau/dispnv50/disp.c | 13 ++++++++++++-
>>   1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
>> index 196612addfd6..1c9c0cdf85db 100644
>> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
>> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
>> @@ -2693,9 +2693,20 @@ nv50_display_create(struct drm_device *dev)
>>   	else
>>   		nouveau_display(dev)->format_modifiers = disp50xx_modifiers;
>>   
>> -	if (disp->disp->object.oclass >= GK104_DISP) {
>> +	/* FIXME: 256x256 cursors are supported on Kepler, however unlike Maxwell and later
>> +	 * generations Kepler requires that we use small pages (4K) for cursor scanout surfaces. The
>> +	 * proper fix for this is to teach nouveau to migrate fbs being used for the cursor plane to
>> +	 * small page allocations in prepare_fb(). When this is implemented, we should also force
>> +	 * large pages (128K) for ovly fbs in order to fix Kepler ovlys.
>> +	 * But until then, just limit cursors to 128x128 - which is small enough to avoid ever using
>> +	 * large pages.
>> +	 */
>> +	if (disp->disp->object.oclass >= GM107_DISP) {
>>   		dev->mode_config.cursor_width = 256;
>>   		dev->mode_config.cursor_height = 256;
>> +	} else if (disp->disp->object.oclass >= GK104_DISP) {
>> +		dev->mode_config.cursor_width = 128;
>> +		dev->mode_config.cursor_height = 128;
>>   	} else {
>>   		dev->mode_config.cursor_width = 64;
>>   		dev->mode_config.cursor_height = 64;
>> -- 
>> 2.29.2
>>