[PATCH v3] drm/ast: Don't check new mode if CRTC is being disabled

[Daniel Vetter]

On Thu, May 07, 2020 at 11:06:40AM +0200, Thomas Zimmermann wrote:
> Suspending failed because there's no mode if the CRTC is being
> disabled. Early-out in this case. This fixes runtime PM for ast.
> 
> v3:
> 	* fixed commit message
> v2:
> 	* added Tested-by/Reported-by tags
> 	* added Fixes tags and CC (Sam)
> 	* improved comment
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> Reported-by: Cary Garrett <cogarre at gmail.com>
> Tested-by: Cary Garrett <cogarre at gmail.com>
> Fixes: b48e1b6ffd28 ("drm/ast: Add CRTC helpers for atomic modesetting")
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: Gerd Hoffmann <kraxel at redhat.com>
> Cc: Dave Airlie <airlied at redhat.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Sam Ravnborg <sam at ravnborg.org>
> Cc: <stable at vger.kernel.org> # v5.6+

Yeah legacy crtc helpers just let you shut stuff off and no checks.

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

> ---
>  drivers/gpu/drm/ast/ast_mode.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
> index 7a9f20a2fd303..0cbbb21edb4e1 100644
> --- a/drivers/gpu/drm/ast/ast_mode.c
> +++ b/drivers/gpu/drm/ast/ast_mode.c
> @@ -801,6 +801,9 @@ static int ast_crtc_helper_atomic_check(struct drm_crtc *crtc,
>  		return -EINVAL;
>  	}
>  
> +	if (!state->enable)
> +		return 0; /* no mode checks if CRTC is being disabled */
> +
>  	ast_state = to_ast_crtc_state(state);
>  
>  	format = ast_state->format;
> -- 
> 2.26.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch