On Fri, 04 Sep 2026, Thomas Zimmermann <[email protected]> wrote:
> Sysfb drivers currently use the given display mode for looking up the
> panel orientation. But the look-up table stores the native geometry of
> the panels, so the lookup fails if the current mode sizes differs.
>
> Get the panel's native geometry with drm_edid_detect_panel_size() from
> the EDID and use it for looking up the panel orientation.
>
> v2:
> - ofdrm: validate EDID header before using it (Sashiko)
>
> Signed-off-by: Thomas Zimmermann <[email protected]>
> Acked-by: Ard Biesheuvel <[email protected]>

Acked-by: Jani Nikula <[email protected]>

> ---
>  drivers/gpu/drm/sysfb/efidrm.c  | 17 ++++++++++++++++-
>  drivers/gpu/drm/sysfb/ofdrm.c   | 18 ++++++++++++++++--
>  drivers/gpu/drm/sysfb/vesadrm.c | 17 ++++++++++++++++-
>  3 files changed, 48 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/sysfb/efidrm.c b/drivers/gpu/drm/sysfb/efidrm.c
> index 3f9cd5d03efb..8b19f437308e 100644
> --- a/drivers/gpu/drm/sysfb/efidrm.c
> +++ b/drivers/gpu/drm/sysfb/efidrm.c
> @@ -152,6 +152,7 @@ static struct efidrm_device *efidrm_device_create(struct 
> drm_driver *drv,
>       const struct screen_info *si;
>       const struct drm_format_info *format;
>       int width, height, stride;
> +     unsigned int panel_width, panel_height;
>       s64 vsize;
>       u64 mem_flags;
>       struct resource resbuf;
> @@ -217,6 +218,20 @@ static struct efidrm_device *efidrm_device_create(struct 
> drm_driver *drv,
>       if (drm_edid_header_is_valid(dpy->edid.dummy) == 8)
>               sysfb->edid = dpy->edid.dummy;
>  #endif
> +
> +     panel_width = width;
> +     panel_height = height;
> +
> +     if (sysfb->edid) {
> +             const struct drm_edid *drm_edid;
> +
> +             drm_edid = drm_edid_alloc(sysfb->edid, EDID_LENGTH);
> +             if (drm_edid) {
> +                     drm_edid_detect_panel_size(drm_edid, &panel_width, 
> &panel_height);
> +                     drm_edid_free(drm_edid);
> +             }
> +     }
> +
>       sysfb->fb_mode = drm_sysfb_mode(width, height, 0, 0);
>       sysfb->fb_format = format;
>       sysfb->fb_pitch = stride;
> @@ -340,7 +355,7 @@ static struct efidrm_device *efidrm_device_create(struct 
> drm_driver *drv,
>       drm_connector_helper_add(connector, &efidrm_connector_helper_funcs);
>       drm_connector_set_panel_orientation_with_quirk(connector,
>                                                      
> DRM_MODE_PANEL_ORIENTATION_UNKNOWN,
> -                                                    width, height);
> +                                                    panel_width, 
> panel_height);
>       if (sysfb->edid)
>               drm_connector_attach_edid_property(connector);
>  
> diff --git a/drivers/gpu/drm/sysfb/ofdrm.c b/drivers/gpu/drm/sysfb/ofdrm.c
> index 9d60db45139c..c41255569854 100644
> --- a/drivers/gpu/drm/sysfb/ofdrm.c
> +++ b/drivers/gpu/drm/sysfb/ofdrm.c
> @@ -229,7 +229,7 @@ static const u8 *display_get_edid_of(struct drm_device 
> *dev, struct device_node
>  {
>       int ret = of_property_read_u8_array(of_node, "EDID", buf, EDID_LENGTH);
>  
> -     if (ret)
> +     if (ret || drm_edid_header_is_valid(buf) != 8)
>               return NULL;
>       return buf;
>  }
> @@ -828,6 +828,7 @@ static struct ofdrm_device *ofdrm_device_create(struct 
> drm_driver *drv,
>       enum ofdrm_model model;
>       bool big_endian;
>       int width, height, depth, linebytes;
> +     unsigned int panel_width, panel_height;
>       const struct drm_format_info *format;
>       u64 address;
>       const u8 *edid;
> @@ -998,6 +999,19 @@ static struct ofdrm_device *ofdrm_device_create(struct 
> drm_driver *drv,
>               sysfb->fb_gamma_lut_size = OFDRM_GAMMA_LUT_SIZE;
>       sysfb->edid = edid;
>  
> +     panel_width = width;
> +     panel_height = height;
> +
> +     if (sysfb->edid) {
> +             const struct drm_edid *drm_edid;
> +
> +             drm_edid = drm_edid_alloc(sysfb->edid, EDID_LENGTH);
> +             if (drm_edid) {
> +                     drm_edid_detect_panel_size(drm_edid, &panel_width, 
> &panel_height);
> +                     drm_edid_free(drm_edid);
> +             }
> +     }
> +
>       drm_dbg(dev, "display mode={" DRM_MODE_FMT "}\n", 
> DRM_MODE_ARG(&sysfb->fb_mode));
>       drm_dbg(dev, "framebuffer format=%p4cc, size=%dx%d, linebytes=%d 
> byte\n",
>               &format->format, width, height, linebytes);
> @@ -1069,7 +1083,7 @@ static struct ofdrm_device *ofdrm_device_create(struct 
> drm_driver *drv,
>       drm_connector_helper_add(connector, &ofdrm_connector_helper_funcs);
>       drm_connector_set_panel_orientation_with_quirk(connector,
>                                                      
> DRM_MODE_PANEL_ORIENTATION_UNKNOWN,
> -                                                    width, height);
> +                                                    panel_width, 
> panel_height);
>       if (edid)
>               drm_connector_attach_edid_property(connector);
>  
> diff --git a/drivers/gpu/drm/sysfb/vesadrm.c b/drivers/gpu/drm/sysfb/vesadrm.c
> index 6a67b2d2e451..f6358a0a68bd 100644
> --- a/drivers/gpu/drm/sysfb/vesadrm.c
> +++ b/drivers/gpu/drm/sysfb/vesadrm.c
> @@ -402,6 +402,7 @@ static struct vesadrm_device 
> *vesadrm_device_create(struct drm_driver *drv,
>       const struct screen_info *si;
>       const struct drm_format_info *format;
>       int width, height, stride;
> +     unsigned int panel_width, panel_height;
>       s64 vsize;
>       struct resource resbuf;
>       struct resource *res;
> @@ -484,6 +485,20 @@ static struct vesadrm_device 
> *vesadrm_device_create(struct drm_driver *drv,
>       if (drm_edid_header_is_valid(dpy->edid.dummy) == 8)
>               sysfb->edid = dpy->edid.dummy;
>  #endif
> +
> +     panel_width = width;
> +     panel_height = height;
> +
> +     if (sysfb->edid) {
> +             const struct drm_edid *drm_edid;
> +
> +             drm_edid = drm_edid_alloc(sysfb->edid, EDID_LENGTH);
> +             if (drm_edid) {
> +                     drm_edid_detect_panel_size(drm_edid, &panel_width, 
> &panel_height);
> +                     drm_edid_free(drm_edid);
> +             }
> +     }
> +
>       sysfb->fb_mode = drm_sysfb_mode(width, height, 0, 0);
>       sysfb->fb_format = format;
>       sysfb->fb_pitch = stride;
> @@ -585,7 +600,7 @@ static struct vesadrm_device 
> *vesadrm_device_create(struct drm_driver *drv,
>       drm_connector_helper_add(connector, &vesadrm_connector_helper_funcs);
>       drm_connector_set_panel_orientation_with_quirk(connector,
>                                                      
> DRM_MODE_PANEL_ORIENTATION_UNKNOWN,
> -                                                    width, height);
> +                                                    panel_width, 
> panel_height);
>       if (sysfb->edid)
>               drm_connector_attach_edid_property(connector);

-- 
Jani Nikula, Intel

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