[PATCH] drm: drm_probe_helper: add modes upto 1920x1080

[PATCH] drm: drm_probe_helper: add modes upto 1920x1080

[Angus Ainslie]

Lots of monitors nowdays support more than 1024x768 so if the EDID is
unknown then add resolutions upto 1920x1080.

Signed-off-by: Angus Ainslie <angus@akkea.ca>
---
 drivers/gpu/drm/drm_probe_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index e7e1ee2aa352..5ad66ae9916e 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -517,7 +517,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 
 	if (count == 0 && (connector->status == connector_status_connected ||
 			   connector->status == connector_status_unknown))
-		count = drm_add_modes_noedid(connector, 1024, 768);
+		count = drm_add_modes_noedid(connector, 1920, 1080);
 	count += drm_helper_probe_add_cmdline_mode(connector);
 	if (count == 0)
 		goto prune;
-- 
2.25.1

Re: [PATCH] drm: drm_probe_helper: add modes upto 1920x1080

[Jani Nikula]

Cc: Ville

On Mon, 15 Nov 2021, Angus Ainslie <angus@akkea.ca> wrote:
> Lots of monitors nowdays support more than 1024x768 so if the EDID is
> unknown then add resolutions upto 1920x1080.

IIUC it's supposed to be the fallback that's pretty much guaranteed to
work. What's going to happen if we add 1920x1080 and it fails?


BR,
Jani.

>
> Signed-off-by: Angus Ainslie <angus@akkea.ca>
> ---
>  drivers/gpu/drm/drm_probe_helper.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index e7e1ee2aa352..5ad66ae9916e 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -517,7 +517,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
>  
>  	if (count == 0 && (connector->status == connector_status_connected ||
>  			   connector->status == connector_status_unknown))
> -		count = drm_add_modes_noedid(connector, 1024, 768);
> +		count = drm_add_modes_noedid(connector, 1920, 1080);
>  	count += drm_helper_probe_add_cmdline_mode(connector);
>  	if (count == 0)
>  		goto prune;

-- 
Jani Nikula, Intel Open Source Graphics Center

Re: [PATCH] drm: drm_probe_helper: add modes upto 1920x1080

[Daniel Vetter]

On Tue, Nov 16, 2021 at 9:44 AM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
>
> Cc: Ville
>
> On Mon, 15 Nov 2021, Angus Ainslie <angus@akkea.ca> wrote:
> > Lots of monitors nowdays support more than 1024x768 so if the EDID is
> > unknown then add resolutions upto 1920x1080.
>
> IIUC it's supposed to be the fallback that's pretty much guaranteed to
> work. What's going to happen if we add 1920x1080 and it fails?

Yeah unless we are now in a times where monitors fail to light up
these very low resolutions then I don't think adding more here is a
good idea. This absolute fallback list is _not_ about making things
good, but about getting anything onto the screen. If we really, really
need this (and then it needs good reasons) then a defensive approach
might be to add more modes, but still leave the old 1024x768 as the
preferred one. That would avoid any regression potential.

Otherwise this just becomes a game of "I want to have the best mode
for my broken screen without working edid as the default", which is
no-go.
-Daniel

> BR,
> Jani.
>
> >
> > Signed-off-by: Angus Ainslie <angus@akkea.ca>
> > ---
> >  drivers/gpu/drm/drm_probe_helper.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> > index e7e1ee2aa352..5ad66ae9916e 100644
> > --- a/drivers/gpu/drm/drm_probe_helper.c
> > +++ b/drivers/gpu/drm/drm_probe_helper.c
> > @@ -517,7 +517,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
> >
> >       if (count == 0 && (connector->status == connector_status_connected ||
> >                          connector->status == connector_status_unknown))
> > -             count = drm_add_modes_noedid(connector, 1024, 768);
> > +             count = drm_add_modes_noedid(connector, 1920, 1080);
> >       count += drm_helper_probe_add_cmdline_mode(connector);
> >       if (count == 0)
> >               goto prune;
>
> --
> Jani Nikula, Intel Open Source Graphics Center



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