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drm/amd/display: Fix wrong handling for AUX_DEFER case

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commit 65924ec69b29296845c7f628112353438e63ea56 upstream.

[Why]
We incorrectly ack all bytes get written when the reply actually is defer.
When it's defer, means sink is not ready for the request. We should
retry the request.

[How]
Only reply all data get written when receive I2C_ACK|AUX_ACK. Otherwise,
reply the number of actual written bytes received from the sink.
Add some messages to facilitate debugging as well.

Fixes: ad6756b4d7 ("drm/amd/display: Shift dc link aux to aux_payload")
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 3637e457eb0000bc37d8bbbec95964aad2fb29fd)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Wayne Lin
2025-04-20 19:22:14 +08:00
committed by Greg Kroah-Hartman
parent 89850f11bb
commit 79d982ae2f
1 changed files with 24 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
View File

@@ -48,6 +48,9 @@
#define PEAK_FACTOR_X1000 1006
/*
* This function handles both native AUX and I2C-Over-AUX transactions.
*/
static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
struct drm_dp_aux_msg *msg)
{
@@ -84,15 +87,25 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
if (adev->dm.aux_hpd_discon_quirk) {
if (msg->address == DP_SIDEBAND_MSG_DOWN_REQ_BASE &&
operation_result == AUX_RET_ERROR_HPD_DISCON) {
result = 0;
result = msg->size;
operation_result = AUX_RET_SUCCESS;
}
}
if (payload.write && result >= 0)
result = msg->size;
/*
* result equals to 0 includes the cases of AUX_DEFER/I2C_DEFER
*/
if (payload.write && result >= 0) {
if (result) {
/*one byte indicating partially written bytes. Force 0 to retry*/
drm_info(adev_to_drm(adev), "amdgpu: AUX partially written\n");
result = 0;
} else if (!payload.reply[0])
/*I2C_ACK|AUX_ACK*/
result = msg->size;
}
if (result < 0)
if (result < 0) {
switch (operation_result) {
case AUX_RET_SUCCESS:
break;
@@ -111,6 +124,13 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
break;
}
drm_info(adev_to_drm(adev), "amdgpu: DP AUX transfer fail:%d\n", operation_result);
}
if (payload.reply[0])
drm_info(adev_to_drm(adev), "amdgpu: AUX reply command not ACK: 0x%02x.",
payload.reply[0]);
return result;
}