On 1/26/2024 16:34, Mario Limonciello wrote:
On 1/26/2024 16:22, Hamza Mahfooz wrote:
We want programs besides the compositor to be able to enable or disable
panel power saving features. However, since they are currently only
configurable through DRM properties, that isn't possible. So, to remedy
that issue introduce a new "panel_power_savings" sysfs attribute.
Cc: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
---
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 59 +++++++++++++++++++
1 file changed, 59 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 cd98b3565178..b3fcd833015d 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6534,6 +6534,58 @@
amdgpu_dm_connector_atomic_duplicate_state(struct drm_connector
*connector)
return &new_state->base;
}
+static ssize_t panel_power_savings_show(struct device *device,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct drm_connector *connector = dev_get_drvdata(device);
+ struct drm_device *dev = connector->dev;
+ ssize_t val;
+
+ drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+ val = to_dm_connector_state(connector->state)->abm_level;
+ drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+ return sysfs_emit(buf, "%lu\n", val);
When the system is first booted up with nothing on the kernel command
line, this emits the value for ABM_LEVEL_IMMEDIATE_DISABLE, which isn't
something we normally should be showing to people.
I think you should be special casing it similar to how the store special
case works.
+}
+
+static ssize_t panel_power_savings_store(struct device *device,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct drm_connector *connector = dev_get_drvdata(device);
+ struct drm_device *dev = connector->dev;
+ long val;
+ int ret;
+
+ ret = kstrtol(buf, 0, &val);
+
+ if (ret)
+ return ret;
+
+ if (val < 0 || val > 4)
+ return -EINVAL;
+
+ drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+ to_dm_connector_state(connector->state)->abm_level = val ?:
+ ABM_LEVEL_IMMEDIATE_DISABLE;
+ drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
It appears that the ABM doesn't actually take effect by writing this
value until the next modeset.
This is also reported by Dominik Förderer. I suggested he try to change
resolutions in his DE and that activated ABM.
So I think it's missing another call to flush out to the hardware.
+ return count;
+}
+
To make this more discoverable I think you want some kerneldoc.
+static DEVICE_ATTR_RW(panel_power_savings);
+
+static struct attribute *amdgpu_attrs[] = {
+ &dev_attr_panel_power_savings.attr,
+ NULL
+};
+
+static const struct attribute_group amdgpu_group = {
+ .name = "amdgpu",
+ .attrs = amdgpu_attrs
+};
+
static int
amdgpu_dm_connector_late_register(struct drm_connector *connector)
{
@@ -6541,6 +6593,13 @@ amdgpu_dm_connector_late_register(struct
drm_connector *connector)
to_amdgpu_dm_connector(connector);
int r;
+ if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
+ r = sysfs_create_group(&connector->kdev->kobj,
+ &amdgpu_group);
+ if (r)
+ return r;
+ }
+
I think there should be some matching code sysfs_remove_group(), maybe
in early_unregister() callback.
amdgpu_dm_register_backlight_device(amdgpu_dm_connector);
if ((connector->connector_type ==
DRM_MODE_CONNECTOR_DisplayPort) ||
