On Wed, 14 Feb 2024, Mario Limonciello <mario.limonciello@xxxxxxx> wrote: > Some manufacturers have intentionally put an EDID that differs from > the EDID on the internal panel on laptops. Drivers that prefer to > fetch this EDID can set a bit on the drm_connector to indicate that > the DRM EDID helpers should try to fetch it and it is preferred if > it's present. I just replied to a previous version of the patch [1]. Looks like all the comments there still hold. BR, Jani. [1] https://lore.kernel.org/r/87eddd6d41.fsf@xxxxxxxxx > > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> > --- > drivers/gpu/drm/Kconfig | 1 + > drivers/gpu/drm/drm_edid.c | 109 +++++++++++++++++++++++++++++++++--- > include/drm/drm_connector.h | 6 ++ > include/drm/drm_edid.h | 1 + > 4 files changed, 109 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index 872edb47bb53..3db89e6af01d 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -8,6 +8,7 @@ > menuconfig DRM > tristate "Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)" > depends on (AGP || AGP=n) && !EMULATED_CMPXCHG && HAS_DMA > + depends on (ACPI_VIDEO || ACPI_VIDEO=n) > select DRM_PANEL_ORIENTATION_QUIRKS > select DRM_KMS_HELPER if DRM_FBDEV_EMULATION > select FB_CORE if DRM_FBDEV_EMULATION > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 923c4423151c..cdc30c6d05d5 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -28,6 +28,7 @@ > * DEALINGS IN THE SOFTWARE. > */ > > +#include <acpi/video.h> > #include <linux/bitfield.h> > #include <linux/cec.h> > #include <linux/hdmi.h> > @@ -2188,6 +2189,58 @@ drm_do_probe_ddc_edid(void *data, u8 *buf, unsigned int block, size_t len) > return ret == xfers ? 0 : -1; > } > > +/** > + * drm_do_probe_acpi_edid() - get EDID information via ACPI _DDC > + * @data: struct drm_connector > + * @buf: EDID data buffer to be filled > + * @block: 128 byte EDID block to start fetching from > + * @len: EDID data buffer length to fetch > + * > + * Try to fetch EDID information by calling acpi_video_get_edid() function. > + * > + * Return: 0 on success or error code on failure. > + */ > +static int > +drm_do_probe_acpi_edid(void *data, u8 *buf, unsigned int block, size_t len) > +{ > + struct drm_connector *connector = data; > + struct drm_device *ddev = connector->dev; > + struct acpi_device *acpidev = ACPI_COMPANION(ddev->dev); > + unsigned char start = block * EDID_LENGTH; > + void *edid; > + int r; > + > + if (!acpidev) > + return -ENODEV; > + > + switch (connector->connector_type) { > + case DRM_MODE_CONNECTOR_LVDS: > + case DRM_MODE_CONNECTOR_eDP: > + break; > + default: > + return -EINVAL; > + } > + > + /* fetch the entire edid from BIOS */ > + r = acpi_video_get_edid(acpidev, ACPI_VIDEO_DISPLAY_LCD, -1, &edid); > + if (r < 0) { > + DRM_DEBUG_KMS("Failed to get EDID from ACPI: %d\n", r); > + return r; > + } > + if (len > r || start > r || start + len > r) { > + r = -EINVAL; > + goto cleanup; > + } > + > + memcpy(buf, edid + start, len); > + r = 0; > + > +cleanup: > + kfree(edid); > + > + return r; > +} > + > static void connector_bad_edid(struct drm_connector *connector, > const struct edid *edid, int num_blocks) > { > @@ -2621,7 +2674,8 @@ EXPORT_SYMBOL(drm_probe_ddc); > * @connector: connector we're probing > * @adapter: I2C adapter to use for DDC > * > - * Poke the given I2C channel to grab EDID data if possible. If found, > + * If the connector allows it, try to fetch EDID data using ACPI. If not found > + * poke the given I2C channel to grab EDID data if possible. If found, > * attach it to the connector. > * > * Return: Pointer to valid EDID or NULL if we couldn't find any. > @@ -2629,20 +2683,50 @@ EXPORT_SYMBOL(drm_probe_ddc); > struct edid *drm_get_edid(struct drm_connector *connector, > struct i2c_adapter *adapter) > { > - struct edid *edid; > + struct edid *edid = NULL; > > if (connector->force == DRM_FORCE_OFF) > return NULL; > > - if (connector->force == DRM_FORCE_UNSPECIFIED && !drm_probe_ddc(adapter)) > - return NULL; > + if (connector->acpi_edid_allowed) > + edid = _drm_do_get_edid(connector, drm_do_probe_acpi_edid, connector, NULL); > + > + if (!edid) { > + if (connector->force == DRM_FORCE_UNSPECIFIED && !drm_probe_ddc(adapter)) > + return NULL; > + edid = _drm_do_get_edid(connector, drm_do_probe_ddc_edid, adapter, NULL); > + } > > - edid = _drm_do_get_edid(connector, drm_do_probe_ddc_edid, adapter, NULL); > drm_connector_update_edid_property(connector, edid); > return edid; > } > EXPORT_SYMBOL(drm_get_edid); > > +/** > + * drm_edid_read_acpi - get EDID data, if available > + * @connector: connector we're probing > + * > + * Use the BIOS to attempt to grab EDID data if possible. > + * > + * The returned pointer must be freed using drm_edid_free(). > + * > + * Return: Pointer to valid EDID or NULL if we couldn't find any. > + */ > +const struct drm_edid *drm_edid_read_acpi(struct drm_connector *connector) > +{ > + const struct drm_edid *drm_edid; > + > + if (connector->force == DRM_FORCE_OFF) > + return NULL; > + > + drm_edid = drm_edid_read_custom(connector, drm_do_probe_acpi_edid, connector); > + > + /* Note: Do *not* call connector updates here. */ > + > + return drm_edid; > +} > +EXPORT_SYMBOL(drm_edid_read_acpi); > + > /** > * drm_edid_read_custom - Read EDID data using given EDID block read function > * @connector: Connector to use > @@ -2727,10 +2811,11 @@ const struct drm_edid *drm_edid_read_ddc(struct drm_connector *connector, > EXPORT_SYMBOL(drm_edid_read_ddc); > > /** > - * drm_edid_read - Read EDID data using connector's I2C adapter > + * drm_edid_read - Read EDID data using BIOS or connector's I2C adapter > * @connector: Connector to use > * > - * Read EDID using the connector's I2C adapter. > + * Read EDID from BIOS if allowed by connector or by using the connector's > + * I2C adapter. > * > * The EDID may be overridden using debugfs override_edid or firmware EDID > * (drm_edid_load_firmware() and drm.edid_firmware parameter), in this priority > @@ -2742,10 +2827,18 @@ EXPORT_SYMBOL(drm_edid_read_ddc); > */ > const struct drm_edid *drm_edid_read(struct drm_connector *connector) > { > + const struct drm_edid *drm_edid = NULL; > + > if (drm_WARN_ON(connector->dev, !connector->ddc)) > return NULL; > > - return drm_edid_read_ddc(connector, connector->ddc); > + if (connector->acpi_edid_allowed) > + drm_edid = drm_edid_read_acpi(connector); > + > + if (!drm_edid) > + drm_edid = drm_edid_read_ddc(connector, connector->ddc); > + > + return drm_edid; > } > EXPORT_SYMBOL(drm_edid_read); > > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h > index fe88d7fc6b8f..74ed47f37a69 100644 > --- a/include/drm/drm_connector.h > +++ b/include/drm/drm_connector.h > @@ -1886,6 +1886,12 @@ struct drm_connector { > > /** @hdr_sink_metadata: HDR Metadata Information read from sink */ > struct hdr_sink_metadata hdr_sink_metadata; > + > + /** > + * @acpi_edid_allowed: Get the EDID from the BIOS, if available. > + * This is only applicable to eDP and LVDS displays. > + */ > + bool acpi_edid_allowed; > }; > > #define obj_to_connector(x) container_of(x, struct drm_connector, base) > diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h > index 7923bc00dc7a..1c1ee927de9c 100644 > --- a/include/drm/drm_edid.h > +++ b/include/drm/drm_edid.h > @@ -459,5 +459,6 @@ bool drm_edid_is_digital(const struct drm_edid *drm_edid); > > const u8 *drm_find_edid_extension(const struct drm_edid *drm_edid, > int ext_id, int *ext_index); > +const struct drm_edid *drm_edid_read_acpi(struct drm_connector *connector); > > #endif /* __DRM_EDID_H__ */ -- Jani Nikula, Intel
