[PATCH v7 10/10] drm/amd/display: Fetch the EDID from _DDC if available for eDP
Mario Limonciello
mario.limonciello at amd.com
Thu Sep 19 16:05:57 UTC 2024
On 9/19/2024 11:03, Alex Hung wrote:
> A minor comment (see inline below).
>
> Otherwise
>
> Reviewed-by: Alex Hung <alex.hung at amd.com>
>
> On 2024-09-18 15:38, Mario Limonciello wrote:
>> Some manufacturers have intentionally put an EDID that differs from
>> the EDID on the internal panel on laptops.
>>
>> Attempt to fetch this EDID if it exists and prefer it over the EDID
>> that is provided by the panel. If a user prefers to use the EDID from
>> the panel, offer a DC debugging parameter that would disable this.
>>
>> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
>> ---
>> .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 62 ++++++++++++++++++-
>> drivers/gpu/drm/amd/include/amd_shared.h | 5 ++
>> 2 files changed, 66 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
>> index 8f4be7a1ec45..05d3e00ecce0 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
>> @@ -23,6 +23,8 @@
>> *
>> */
>> +#include <acpi/video.h>
>> +
>> #include <linux/string.h>
>> #include <linux/acpi.h>
>> #include <linux/i2c.h>
>> @@ -874,6 +876,60 @@ bool dm_helpers_is_dp_sink_present(struct dc_link
>> *link)
>> return dp_sink_present;
>> }
>> +static int
>> +dm_helpers_probe_acpi_edid(void *data, u8 *buf, unsigned int block,
>> size_t len)
>> +{
>> + struct drm_connector *connector = data;
>> + struct acpi_device *acpidev = ACPI_COMPANION(connector->dev->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 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 const struct drm_edid *
>> +dm_helpers_read_acpi_edid(struct amdgpu_dm_connector *aconnector)
>> +{
>> + struct drm_connector *connector = &aconnector->base;
>> +
>> + if (amdgpu_dc_debug_mask & DC_DISABLE_ACPI_EDID)
>> + return 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;
>> +
>> + return drm_edid_read_custom(connector,
>> dm_helpers_probe_acpi_edid, connector);
>> +}
>> +
>> enum dc_edid_status dm_helpers_read_local_edid(
>> struct dc_context *ctx,
>> struct dc_link *link,
>> @@ -896,7 +952,11 @@ enum dc_edid_status dm_helpers_read_local_edid(
>> * do check sum and retry to make sure read correct edid.
>> */
>> do {
>> - drm_edid = drm_edid_read_ddc(connector, ddc);
>> + drm_edid = dm_helpers_read_acpi_edid(aconnector);
>> + if (drm_edid)
>> + DRM_DEBUG_KMS("Using ACPI provided EDID for %s\n",
>> connector->name);
>
> It is better to always output a message when ACPI's EDID is used without
> enabling any debug options. How about DRM_INFO?
Thanks, DRM_INFO makes sense for discoverability and will adjust it.
>
>> + else
>> + drm_edid = drm_edid_read_ddc(connector, ddc);
>> drm_edid_connector_update(connector, drm_edid);
>> aconnector->drm_edid = drm_edid;
>> diff --git a/drivers/gpu/drm/amd/include/amd_shared.h
>> b/drivers/gpu/drm/amd/include/amd_shared.h
>> index 3f91926a50e9..1ec7c5e5249e 100644
>> --- a/drivers/gpu/drm/amd/include/amd_shared.h
>> +++ b/drivers/gpu/drm/amd/include/amd_shared.h
>> @@ -337,6 +337,11 @@ enum DC_DEBUG_MASK {
>> * @DC_FORCE_IPS_ENABLE: If set, force enable all IPS, all the
>> time.
>> */
>> DC_FORCE_IPS_ENABLE = 0x4000,
>> + /**
>> + * @DC_DISABLE_ACPI_EDID: If set, don't attempt to fetch EDID for
>> + * eDP display from ACPI _DDC method.
>> + */
>> + DC_DISABLE_ACPI_EDID = 0x8000,
>> };
>> enum amd_dpm_forced_level;
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