[PATCH 5.18 128/231] drm/amd/display: Ignore First MST Sideband Message Return Error

Greg Kroah-Hartman
2022-07-19T13:03:42Z

From: Fangzhi Zuo <Jerry.Zuo@amd.com>

[ Upstream commit acea108fa067d140bd155161a79b1fcd967f4137 ]

[why]
First MST sideband message returns AUX_RET_ERROR_HPD_DISCON
on certain intel platform. Aux transaction considered failure
if HPD unexpected pulled low. The actual aux transaction success
in such case, hence do not return error.

[how]
Not returning error when AUX_RET_ERROR_HPD_DISCON detected
on the first sideband message.

v2: squash in additional DMI entries
v3: squash in static fix

Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 39 +++++++++++++++++++
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 8 ++++
.../display/amdgpu_dm/amdgpu_dm_mst_types.c | 17 ++++++++
3 files changed, 64 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index b55a433e829e..bfbd701a4c9a 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -72,6 +72,7 @@
#include <linux/pci.h>
#include <linux/firmware.h>
#include <linux/component.h>
+#include <linux/dmi.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_uapi.h>
@@ -1391,6 +1392,41 @@ static bool dm_should_disable_stutter(struct pci_dev *pdev)
return false;
}

+static const struct dmi_system_id hpd_disconnect_quirk_table[] = {
+ {
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Precision 3660"),
+ },
+ },
+ {
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Precision 3260"),
+ },
+ },
+ {
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Precision 3460"),
+ },
+ },
+ {}
+};
+
+static void retrieve_dmi_info(struct amdgpu_display_manager *dm)
+{
+ const struct dmi_system_id *dmi_id;
+
+ dm->aux_hpd_discon_quirk = false;
+
+ dmi_id = dmi_first_match(hpd_disconnect_quirk_table);
+ if (dmi_id) {
+ dm->aux_hpd_discon_quirk = true;
+ DRM_INFO("aux_hpd_discon_quirk attached\n");
+ }
+}
+
static int amdgpu_dm_init(struct amdgpu_device *adev)
{
struct dc_init_data init_data;
@@ -1521,6 +1557,9 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
}

INIT_LIST_HEAD(&adev->dm.da_list);
+
+ retrieve_dmi_info(&adev->dm);
+
/* Display Core create. */
adev->dm.dc = dc_create(&init_data);

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 7e44b0429448..4844601a5f47 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -546,6 +546,14 @@ struct amdgpu_display_manager {
* last successfully applied backlight values.
*/
u32 actual_brightness[AMDGPU_DM_MAX_NUM_EDP];
+
+ /**
+ * @aux_hpd_discon_quirk:
+ *
+ * quirk for hpd discon while aux is on-going.
+ * occurred on certain intel platform
+ */
+ bool aux_hpd_discon_quirk;
};

enum dsc_clock_force_state {
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 31ac1fce36f8..d864cae1af67 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -58,6 +58,8 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
ssize_t result = 0;
struct aux_payload payload;
enum aux_return_code_type operation_result;
+ struct amdgpu_device *adev;
+ struct ddc_service *ddc;

if (WARN_ON(msg->size > 16))
return -E2BIG;
@@ -76,6 +78,21 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
result = dc_link_aux_transfer_raw(TO_DM_AUX(aux)->ddc_service, &payload,
&operation_result);

+ /*
+ * w/a on certain intel platform where hpd is unexpected to pull low during
+ * 1st sideband message transaction by return AUX_RET_ERROR_HPD_DISCON
+ * aux transaction is succuess in such case, therefore bypass the error
+ */
+ ddc = TO_DM_AUX(aux)->ddc_service;
+ adev = ddc->ctx->driver_context;
+ 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;
+ operation_result = AUX_RET_SUCCESS;
+ }
+ }
+
if (payload.write && result >= 0)
result = msg->size;

--
2.35.1