On Thu, 01 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 can call this
> helper to attempt to fetch the EDID from the BIOS's ACPI _DDC method.
I'm really not happy about adding new struct edid based APIs to
drm_edid.[ch]. Everything new should be struct drm_edid based. All
drivers should be converting towards struct drm_edid, instead of adding
more legacy to rip out later.
BR,
Jani.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---
> v1->v2:
> * Split code from previous amdgpu specific helper to generic drm helper.
> v2->v3:
> * Add an extra select to fix a variety of randconfig errors found from
> LKP robot.
> ---
> drivers/gpu/drm/Kconfig | 5 +++
> drivers/gpu/drm/drm_edid.c | 73 ++++++++++++++++++++++++++++++++++++++
> include/drm/drm_edid.h | 1 +
> 3 files changed, 79 insertions(+)
>
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 2520db0b776e..14df907c96c8 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -21,6 +21,11 @@ menuconfig DRM
> select KCMP
> select VIDEO_CMDLINE
> select VIDEO_NOMODESET
> + select ACPI_VIDEO if ACPI
> + select BACKLIGHT_CLASS_DEVICE if ACPI
> + select INPUT if ACPI
> + select X86_PLATFORM_DEVICES if ACPI && X86
> + select ACPI_WMI if ACPI && X86
> help
> Kernel-level support for the Direct Rendering Infrastructure (DRI)
> introduced in XFree86 4.0. If you say Y here, you need to select
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 69c68804023f..1fbbeaa664b2 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 +2189,47 @@ 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_device
> + * @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_device *ddev = data;
> + struct acpi_device *acpidev = ACPI_COMPANION(ddev->dev);
> + unsigned char start = block * EDID_LENGTH;
> + void *edid;
> + int r;
> +
> + if (!acpidev)
> + return -ENODEV;
> +
> + /* 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 -EINVAL;
> + }
> + 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)
> {
> @@ -2643,6 +2685,37 @@ struct edid *drm_get_edid(struct drm_connector *connector,
> }
> EXPORT_SYMBOL(drm_get_edid);
>
> +/**
> + * drm_get_acpi_edid - get EDID data, if available
> + * @connector: connector we're probing
> + *
> + * Use the BIOS to attempt 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.
> + */
> +struct edid *drm_get_acpi_edid(struct drm_connector *connector)
> +{
> + struct edid *edid = NULL;
> +
> + switch (connector->connector_type) {
> + case DRM_MODE_CONNECTOR_LVDS:
> + case DRM_MODE_CONNECTOR_eDP:
> + break;
> + default:
> + return NULL;
> + }
> +
> + if (connector->force == DRM_FORCE_OFF)
> + return NULL;
> +
> + edid = _drm_do_get_edid(connector, drm_do_probe_acpi_edid, connector->dev, NULL);
> +
> + drm_connector_update_edid_property(connector, edid);
> + return edid;
> +}
> +EXPORT_SYMBOL(drm_get_acpi_edid);
> +
> /**
> * drm_edid_read_custom - Read EDID data using given EDID block read function
> * @connector: Connector to use
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index 518d1b8106c7..60fbdc06badc 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -412,6 +412,7 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
> void *data);
> struct edid *drm_get_edid(struct drm_connector *connector,
> struct i2c_adapter *adapter);
> +struct edid *drm_get_acpi_edid(struct drm_connector *connector);
> u32 drm_edid_get_panel_id(struct i2c_adapter *adapter);
> struct edid *drm_get_edid_switcheroo(struct drm_connector *connector,
> struct i2c_adapter *adapter);
--
Jani Nikula, Intel
