Re: [PATCH v4 3/3] drm/sysfb: Use preferred panel size for panel orientation quirks

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 04 Sep 2026, Thomas Zimmermann <tzimmermann@suse.de> 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 <tzimmermann@suse.de>
> Acked-by: Ard Biesheuvel <ardb@kernel.org>

Acked-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  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