drm/amd/display: Expose connector VRR range via debugfs

[Why]
It's useful to know the min and max vrr range for IGT testing.

[How]
Expose the min and max vfreq for the connector via a debugfs file
on the connector, "vrr_range".

Example usage: cat /sys/kernel/debug/dri/0/DP-1/vrr_range

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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 9a7ac58eb18ea702383df1548e7013484b1edf62..ddd75a4d8ba5d4e19b0bc32c4fac813b43c91056 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
@@ -671,6 +671,25 @@ static ssize_t dp_phy_test_pattern_debugfs_write(struct file *f, const char __us
        return bytes_from_user;
 }
 
+/*
+ * Returns the min and max vrr vfreq through the connector's debugfs file.
+ * Example usage: cat /sys/kernel/debug/dri/0/DP-1/vrr_range
+ */
+static int vrr_range_show(struct seq_file *m, void *data)
+{
+       struct drm_connector *connector = m->private;
+       struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
+
+       if (connector->status != connector_status_connected)
+               return -ENODEV;
+
+       seq_printf(m, "Min: %u\n", (unsigned int)aconnector->min_vfreq);
+       seq_printf(m, "Max: %u\n", (unsigned int)aconnector->max_vfreq);
+
+       return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(vrr_range);
+
 static const struct file_operations dp_link_settings_debugfs_fops = {
        .owner = THIS_MODULE,
        .read = dp_link_settings_read,
@@ -697,7 +716,8 @@ static const struct {
 } dp_debugfs_entries[] = {
                {"link_settings", &dp_link_settings_debugfs_fops},
                {"phy_settings", &dp_phy_settings_debugfs_fop},
-               {"test_pattern", &dp_phy_test_pattern_fops}
+               {"test_pattern", &dp_phy_test_pattern_fops},
+               {"vrr_range", &vrr_range_fops}
 };
 
 int connector_debugfs_init(struct amdgpu_dm_connector *connector)