Re: [PATCHv2] drm: fb_helper: prefer to use mode, which is not DRM_MODE_TYPE_USERDEF

Radek Dostál
2015-04-20T10:57:41Z

Hi Chris,

On 04/20/2015 12:48 PM, Chris Wilson wrote:
>> Unfortunately you can not do that. I already tried. At the time when
>> > drm_helper_probe_add_cmdline_mode is called EDID informations are not
>> > yet available.
> My understanding is that it should be. fb_helper.initial_config does a
> probe first, and the intel_fb_initial_config() should only keep the
> active mode.

uff, sorry I am not sure that I follow here - I am not that familiar
with the whole subsystem.

>> > Only option would be to remove the GTF cmdline mode, when matching mode
>> > is found in EDID.
> So basically
>
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index 6350387..9212bec 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -79,13 +79,29 @@ drm_mode_validate_flag(const struct drm_display_mode *mode,
>
> static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
> {
> + struct drm_cmdline_mode *cmdline_mode;
> struct drm_display_mode *mode;
>
> - if (!connector->cmdline_mode.specified)
> + cmdline_mode = &connector->cmdline_mode;
> + if (!cmdline_mode->specified)
> return 0;
>
> + /* Only add a GTF mode if we find no matching probed modes */
> + list_for_each_entry(mode, &connector->modes, head) {
> + if (mode->hdisplay != cmdline_mode->xres ||
> + mode->vdisplay != cmdline_mode->yres)
> + continue;
> +
> + if (cmdline_mode->refresh_specified) {
> + if (mode->vrefresh != cmdline_mode->refresh)
> + continue;
> + }
> +
> + return 0;
> + }
> +
> mode = drm_mode_create_from_cmdline_mode(connector->dev,
> - &connector->cmdline_mode);
> + cmdline_mode);
> if (mode == NULL)
> return 0;
>
>
>
> is not sufficient?

indeed, this was my first idea how to fix this problem, but at the time
drm_helper_probe_add_cmdline_mode is called connector->modes is empty =>
the GTF cmdline mode is still added.

Thanks,
Radek