[PATCH] drm: Add downclock quirk for Samsung LTN121AT10-301

[Sean Paul]

On Wed, Jan 18, 2012 at 10:06 AM, Sean Paul <seanpaul at chromium.org> wrote:
> Add a quirk which adds a new downclocked mode to the EDID of Samsung
> LTN121AT10-301 panels. This allows the intel driver to apply downclocking
> and save power.
>

Is there any feedback on the patch? I'd like to get it merged if possible.

Thanks,

Sean

> Signed-off-by: Sean Paul <seanpaul at chromium.org>
> ---
>  drivers/gpu/drm/drm_edid.c |   47 ++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 47 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 7425e5c..e2e3d9b 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -65,6 +65,8 @@
>  #define EDID_QUIRK_FIRST_DETAILED_PREFERRED    (1 << 5)
>  /* use +hsync +vsync for detailed mode */
>  #define EDID_QUIRK_DETAILED_SYNC_PP            (1 << 6)
> +/* the panel supports, but does not include a lower clocked mode for lvds */
> +#define EDID_QUIRK_ADD_DOWNCLOCK_MODE          (1 << 7)
>
>  struct detailed_mode_closure {
>        struct drm_connector *connector;
> @@ -119,6 +121,18 @@ static struct edid_quirk {
>        /* Samsung SyncMaster 22[5-6]BW */
>        { "SAM", 596, EDID_QUIRK_PREFER_LARGE_60 },
>        { "SAM", 638, EDID_QUIRK_PREFER_LARGE_60 },
> +
> +       /* Samsung TFT-LCD LTN121AT10-301 */
> +       { "SEC", 0x3142, EDID_QUIRK_ADD_DOWNCLOCK_MODE },
> +};
> +
> +static struct downclock_rate {
> +       char *vendor;
> +       int product_id;
> +       int clock;
> +} downclock_rate_list[] = {
> +       /* Samsung TFT-LCD LTN121AT10-301 */
> +       { "SEC", 0x3142, 56428},
>  };
>
>  /*** DDC fetch and block validation ***/
> @@ -481,6 +495,36 @@ static void edid_fixup_preferred(struct drm_connector *connector,
>        preferred_mode->type |= DRM_MODE_TYPE_PREFERRED;
>  }
>
> +static int edid_add_downclock(struct drm_connector *connector,
> +                              struct edid *edid)
> +{
> +       struct drm_display_mode *t, *cur_mode, *downclock_mode;
> +       struct downclock_rate *rate;
> +       int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(downclock_rate_list); i++) {
> +               rate = &downclock_rate_list[i];
> +
> +               if (edid_vendor(edid, rate->vendor) &&
> +                   (EDID_PRODUCT_ID(edid) == rate->product_id))
> +                       break;
> +       }
> +       if (i == ARRAY_SIZE(downclock_rate_list))
> +               return 0;
> +
> +       list_for_each_entry_safe(cur_mode, t, &connector->probed_modes, head) {
> +               if (!(cur_mode->type & DRM_MODE_TYPE_PREFERRED))
> +                       continue;
> +
> +               downclock_mode = drm_mode_duplicate(connector->dev, cur_mode);
> +               downclock_mode->type &= ~DRM_MODE_TYPE_PREFERRED;
> +               downclock_mode->clock = rate->clock;
> +               drm_mode_probed_add(connector, downclock_mode);
> +               return 1;
> +       }
> +       return 0;
> +}
> +
>  struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
>                                           int hsize, int vsize, int fresh)
>  {
> @@ -1554,6 +1598,9 @@ int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
>        if (quirks & (EDID_QUIRK_PREFER_LARGE_60 | EDID_QUIRK_PREFER_LARGE_75))
>                edid_fixup_preferred(connector, quirks);
>
> +       if (quirks & EDID_QUIRK_ADD_DOWNCLOCK_MODE)
> +               num_modes += edid_add_downclock(connector, edid);
> +
>        drm_add_display_info(edid, &connector->display_info);
>
>        return num_modes;
> --
> 1.7.7.3
>