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drm/amd/display: Correct the reply value when AUX write incomplete

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[Why]
Now forcing aux->transfer to return 0 when incomplete AUX write is
inappropriate. It should return bytes have been transferred.

[How]
aux->transfer is asked not to change original msg except reply field of
drm_dp_aux_msg structure. Copy the msg->buffer when it's write request,
and overwrite the first byte when sink reply 1 byte indicating partially
written byte number. Then we can return the correct value without
changing the original msg.

Fixes: 3637e457eb ("drm/amd/display: Fix wrong handling for AUX_DEFER case")
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Ray Wu <ray.wu@amd.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 7ac37f0dcd)
Cc: stable@vger.kernel.org
This commit is contained in:
Wayne Lin
2025-04-25 14:44:02 +08:00
committed by Alex Deucher
parent 2d73b0845a
commit d433981385
2 changed files with 10 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
View File

@@ -12763,7 +12763,8 @@ int amdgpu_dm_process_dmub_aux_transfer_sync(
/* The reply is stored in the top nibble of the command. */
payload->reply[0] = (adev->dm.dmub_notify->aux_reply.command >> 4) & 0xF;
if (!payload->write && p_notify->aux_reply.length)
/*write req may receive a byte indicating partially written number as well*/
if (p_notify->aux_reply.length)
memcpy(payload->data, p_notify->aux_reply.data,
p_notify->aux_reply.length);

10
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
View File

@@ -62,6 +62,7 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
enum aux_return_code_type operation_result;
struct amdgpu_device *adev;
struct ddc_service *ddc;
uint8_t copy[16];
if (WARN_ON(msg->size > 16))
return -E2BIG;
@@ -77,6 +78,11 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
(msg->request & DP_AUX_I2C_WRITE_STATUS_UPDATE) != 0;
payload.defer_delay = 0;
if (payload.write) {
memcpy(copy, msg->buffer, msg->size);
payload.data = copy;
}
result = dc_link_aux_transfer_raw(TO_DM_AUX(aux)->ddc_service, &payload,
&operation_result);
@@ -100,9 +106,9 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
*/
if (payload.write && result >= 0) {
if (result) {
/*one byte indicating partially written bytes. Force 0 to retry*/
/*one byte indicating partially written bytes*/
drm_info(adev_to_drm(adev), "amdgpu: AUX partially written\n");
result = 0;
result = payload.data[0];
} else if (!payload.reply[0])
/*I2C_ACK|AUX_ACK*/
result = msg->size;