[REBASE 3/5] drm: Expose modes with aspect ratio, only if requested

[Ville Syrjälä]

On Fri, Nov 24, 2017 at 02:36:17PM +0530, Sharma, Shashank wrote:
> Regards
> 
> Shashank
> 
> 
> On 11/21/2017 10:41 PM, Ville Syrjälä wrote:
> > On Fri, Nov 17, 2017 at 03:00:30PM +0530, Shashank Sharma wrote:
> >> From: aknautiy <ankit.k.nautiyal at intel.com>
> >>
> >> We parse the EDID and add all the modes in the connector's
> >> modelist. This adds CEA modes with aspect ratio information
> >> too, regadless of if user space requested this information or
> >> not.
> >>
> >> This patch prunes the modes with aspect-ratio information, from
> >> a connector's modelist, if the user-space has not set the aspect
> >> ratio DRM client cap.
> >>
> >> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> >> Cc: Shashank Sharma <shashank.sharma at intel.com>
> >> Cc: Jose Abreu <jose.abreu at synopsys.com>
> >>
> >> Signed-off-by: aknautiy <ankit.k.nautiyal at intel.com>
> >> ---
> >>   drivers/gpu/drm/drm_connector.c | 7 +++++++
> >>   1 file changed, 7 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> >> index 704fc89..a246bb5 100644
> >> --- a/drivers/gpu/drm/drm_connector.c
> >> +++ b/drivers/gpu/drm/drm_connector.c
> >> @@ -1285,6 +1285,13 @@ static bool drm_mode_expose_to_userspace(const struct drm_display_mode *mode,
> >>   	 */
> >>   	if (!file_priv->stereo_allowed && drm_mode_is_stereo(mode))
> >>   		return false;
> >> +	/*
> >> +	 * If user-space hasn't configured the driver to expose the modes
> >> +	 * with aspect-ratio, don't expose them.
> >> +	 */
> >> +	if (!file_priv->aspect_ratio_allowed &&
> >> +	    mode->picture_aspect_ratio != HDMI_PICTURE_ASPECT_NONE)
> >> +		return false;
> > I don't think we can just blindly drop the modes. We would have to
> > expose them with the aspect ratio cleared. That could lead to
> > duplicates, but I'm thinking that shouldn't be a real problem for
> > userspace. Having to filteri out the duplicates would certainly
> > complicate things a bit.
> Yes, Agree. Even I was thinking that the right way should be to:
> - add a drm_mode_equal_no_aspect function (like 
> drm_mode_equal_no_clock_no_stereo).

Or just drm_mode_match() with the right flags ;)

> - clear the aspect ratio information from the mode, when not asked for.
> - check the sorted connector->modes list for duplicates for this mode, 
> using above function.
>      - if mode exists, remove it from the list
>      - if not, keep it in the list

Hmm. Since the list should be sorted I guess this won't even have to
traverse the list mutliple times. We can just keep skipping modes as
long they match the last mode we've already decided to expose.

> 
> Sounds like a plan ?
> 
> - Shashank
> >>   
> >>   	return true;
> >>   }
> >> -- 
> >> 2.7.4

-- 
Ville Syrjälä
Intel OTC