[Nouveau] [PATCH v2] drm/nouveau/kms/nve4-nv108: Don't advertise 256x256 cursor support yet

[Roy Spliet]

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

Op 05-03-2021 om 22:21 schreef Lyude Paul:
> While Kepler does technically support 256x256 cursors, it turns out that
> in order for us to use these correctly we need to make sure that the cursor
> plane uses a ctxdma that is set to use small (4K)/large (128K) pages -
> whichever is applicable to the given cursor surface.
> 
> Right now however, we share the main kmsVramCtxDma that is used for all but
> the ovly plane which defaults to small pages - resulting in artifacts when
> we use 256x256 cursor surfaces. So until we teach nouveau to use a separate
> ctxdma for the cursor, let's just stop advertising 256x256 cursors by
> default - which should fix the issues that users were seeing.
> 
> Coincidentally - this is also why small ovlys don't work on Kepler: the
> ctxdma we use for ovlys is set to large pages.
> 
> Changes since v2:
> * Fix comments and patch description
> 
> 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+
> ---
>   drivers/gpu/drm/nouveau/dispnv50/disp.c | 12 +++++++++++-
>   1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> index 196612addfd6..d92cf9e17ac3 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> @@ -2693,9 +2693,19 @@ 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 specify the page type, small (4K) or large (128K),
> +	 * correctly for the ctxdma being used on curs/ovly. We currently share a ctxdma across all
> +	 * display planes (except ovly) that defaults to small pages, which results in artifacting
> +	 * on 256x256 cursors. Until we teach nouveau to create an appropriate ctxdma for the cursor
> +	 * fb in use, simply avoid advertising support for 256x256 cursors.
> +	 */
> +	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;
>