drm/amd/display: Ignore First MST Sideband Message Return Error

From Fangzhi Zuo
c7720f23bb93628f30f16d033eaefbe2540f1b5e in linux 5.15.y/5.15.58
acea108fa067d140bd155161a79b1fcd967f4137 in mainline linux

diff --git a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index d00bae5..94149da 100644 (file)
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -70,6 +70,7 @@
 #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>
@@ -1346,6 +1347,41 @@ 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;
@@ -1437,6 +1473,9 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
        init_data.flags.power_down_display_on_boot = true;
 
        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/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 24231c9..13183b1 100644 (file)
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -539,6 +539,14 @@ 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/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index 74885ff..652cf10 100644 (file)
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -55,6 +55,8 @@ 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;
@@ -71,6 +73,21 @@ 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;