From: Fangzhi Zuo <jerry.zuo@xxxxxxx>
When using debugfs to change MST link settings, we need to wait until
the next stream update to apply the preferred link setting. So, trigger
a hotplug event right after the preferred link setting is applied.
Reviewed-by: Wayne Lin <wayne.lin@xxxxxxx>
Acked-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
Signed-off-by: Fangzhi Zuo <jerry.zuo@xxxxxxx>
---
.../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 156 +++++++++++++++++-
1 file changed, 155 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
index 5ea3284b2b77..d63ee636483b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
@@ -336,6 +336,153 @@ static ssize_t dp_link_settings_write(struct file *f, const char __user *buf,
return size;
}
+static bool dp_mst_is_end_device(struct amdgpu_dm_connector *aconnector)
+{
+ bool is_end_device = false;
+ struct drm_dp_mst_topology_mgr *mgr = NULL;
+ struct drm_dp_mst_port *port = NULL;
+
+ if (aconnector->mst_root && aconnector->mst_root->mst_mgr.mst_state) {
+ mgr = &aconnector->mst_root->mst_mgr;
+ port = aconnector->mst_output_port;
+
+ drm_modeset_lock(&mgr->base.lock, NULL);
+ if (port->pdt == DP_PEER_DEVICE_SST_SINK ||
+ port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV)
+ is_end_device = true;
+ drm_modeset_unlock(&mgr->base.lock);
+ }
+
+ return is_end_device;
+}
+
+/* Change MST link setting
+ *
+ * valid lane count value: 1, 2, 4
+ * valid link rate value:
+ * 06h = 1.62Gbps per lane
+ * 0Ah = 2.7Gbps per lane
+ * 0Ch = 3.24Gbps per lane
+ * 14h = 5.4Gbps per lane
+ * 1Eh = 8.1Gbps per lane
+ * 3E8h = 10.0Gbps per lane
+ * 546h = 13.5Gbps per lane
+ * 7D0h = 20.0Gbps per lane
+ *
+ * debugfs is located at /sys/kernel/debug/dri/0/DP-x/mst_link_settings
+ *
+ * for example, to force to 2 lane, 10.0GHz,
+ * echo 2 0x3e8 > /sys/kernel/debug/dri/0/DP-x/mst_link_settings
+ *
+ * Valid input will trigger hotplug event to get new link setting applied
+ * Invalid input will trigger training setting reset
+ *
+ * The usage can be referred to link_settings entry
+ *
+ */
+static ssize_t dp_mst_link_setting(struct file *f, const char __user *buf,
+ size_t size, loff_t *pos)
+{
+ struct amdgpu_dm_connector *aconnector = file_inode(f)->i_private;
+ struct dc_link *link = aconnector->dc_link;
+ struct amdgpu_device *adev = drm_to_adev(aconnector->base.dev);
+ struct dc *dc = (struct dc *)link->dc;
+ struct dc_link_settings prefer_link_settings;
+ char *wr_buf = NULL;
+ const uint32_t wr_buf_size = 40;
+ /* 0: lane_count; 1: link_rate */
+ int max_param_num = 2;
+ uint8_t param_nums = 0;
+ long param[2];
+ bool valid_input = true;
+
+ if (!dp_mst_is_end_device(aconnector))
+ return -EINVAL;
+
+ if (size == 0)
+ return -EINVAL;
+
+ wr_buf = kcalloc(wr_buf_size, sizeof(char), GFP_KERNEL);
+ if (!wr_buf)
+ return -ENOSPC;
+
+ if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
+ (long *)param, buf,
+ max_param_num,
+ ¶m_nums)) {
+ kfree(wr_buf);
+ return -EINVAL;
+ }
+
+ if (param_nums <= 0) {
+ kfree(wr_buf);
+ DRM_DEBUG_DRIVER("user data not be read\n");
+ return -EINVAL;
+ }
+
+ switch (param[0]) {
+ case LANE_COUNT_ONE:
+ case LANE_COUNT_TWO:
+ case LANE_COUNT_FOUR:
+ break;
+ default:
+ valid_input = false;
+ break;
+ }
+
+ switch (param[1]) {
+ case LINK_RATE_LOW:
+ case LINK_RATE_HIGH:
+ case LINK_RATE_RBR2:
+ case LINK_RATE_HIGH2:
+ case LINK_RATE_HIGH3:
+ case LINK_RATE_UHBR10:
+ case LINK_RATE_UHBR13_5:
+ case LINK_RATE_UHBR20:
+ break;
+ default:
+ valid_input = false;
+ break;
+ }
+
+ if (!valid_input) {
+ kfree(wr_buf);
+ DRM_DEBUG_DRIVER("Invalid Input value No HW will be programmed\n");
+ mutex_lock(&adev->dm.dc_lock);
+ dc_link_set_preferred_training_settings(dc, NULL, NULL, link, false);
+ mutex_unlock(&adev->dm.dc_lock);
+ return -EINVAL;
+ }
+
+ /* save user force lane_count, link_rate to preferred settings
+ * spread spectrum will not be changed
+ */
+ prefer_link_settings.link_spread = link->cur_link_settings.link_spread;
+ prefer_link_settings.use_link_rate_set = false;
+ prefer_link_settings.lane_count = param[0];
+ prefer_link_settings.link_rate = param[1];
+
+ /* skip immediate retrain, and train to new link setting after hotplug event triggered */
+ mutex_lock(&adev->dm.dc_lock);
+ dc_link_set_preferred_training_settings(dc, &prefer_link_settings, NULL, link, true);
+ mutex_unlock(&adev->dm.dc_lock);
+
+ mutex_lock(&aconnector->base.dev->mode_config.mutex);
+ aconnector->base.force = DRM_FORCE_OFF;
+ mutex_unlock(&aconnector->base.dev->mode_config.mutex);
+ drm_kms_helper_hotplug_event(aconnector->base.dev);
+
+ msleep(100);
+
+ mutex_lock(&aconnector->base.dev->mode_config.mutex);
+ aconnector->base.force = DRM_FORCE_UNSPECIFIED;
+ mutex_unlock(&aconnector->base.dev->mode_config.mutex);
+ drm_kms_helper_hotplug_event(aconnector->base.dev);
+
+ kfree(wr_buf);
+ return size;
+}
+
/* function: get current DP PHY settings: voltage swing, pre-emphasis,
* post-cursor2 (defined by VESA DP specification)
*
@@ -2668,6 +2815,12 @@ static const struct file_operations dp_dsc_disable_passthrough_debugfs_fops = {
.llseek = default_llseek
};
+static const struct file_operations dp_mst_link_settings_debugfs_fops = {
+ .owner = THIS_MODULE,
+ .write = dp_mst_link_setting,
+ .llseek = default_llseek
+};
+
static const struct {
char *name;
const struct file_operations *fops;
@@ -2691,7 +2844,8 @@ static const struct {
{"dsc_disable_passthrough", &dp_dsc_disable_passthrough_debugfs_fops},
{"is_mst_connector", &dp_is_mst_connector_fops},
{"mst_progress_status", &dp_mst_progress_status_fops},
- {"is_dpia_link", &is_dpia_link_fops}
+ {"is_dpia_link", &is_dpia_link_fops},
+ {"mst_link_settings", &dp_mst_link_settings_debugfs_fops}
};
static const struct {
--
2.40.1
