amdgpu: multiple CRTC support, DPMS/EDID properties, set_property dispatch

- Support 4 CRTCs instead of hardcoded 1 (AMD GPUs have 4-6 CRTCs)

- Add CONN_PROP_DPMS (ID 31) and CONN_PROP_EDID (ID 32) connector properties.
  DPMS is an enum property (On/Standby/Suspend/Off). EDID is an immutable blob.

- Add DrmModeObjSetPropertyWire struct and wire OBJ_SETPROPERTY ioctl to
  call driver.set_property() with proper error dispatch. Unknown properties
  are silently ignored (not errors).

- Add set_property() to GpuDriver trait with default Unsupported impl.
  AmdDriver implements DPMS property set by mapping connector_id -> CRTC and
  calling DisplayCore::set_dpms().

local/recipes/gpu/redox-drm/source/src/driver.rs

@@ -123,6 +123,10 @@ pub trait GpuDriver: Send + Sync {
         Ok(None)
     }
 
+    fn set_property(&self, _obj_id: u32, _prop_id: u32, _value: u64) -> Result<()> {
+        Err(DriverError::Unsupported("property setting not implemented for this backend"))
+    }
+
     fn redox_private_cs_submit(
         &self,
         _submit: &RedoxPrivateCsSubmit,

local/recipes/gpu/redox-drm/source/src/drivers/amd/mod.rs

@@ -164,7 +164,10 @@ impl AmdDriver {
             display,
             gem: Mutex::new(GemManager::new()),
             connectors: Mutex::new(connectors),
-            crtcs: Mutex::new(vec![Crtc::new(1)]),
+            crtcs: Mutex::new({
+                let count = 4usize;
+                (1..=count).map(|id| Crtc::new(id as u32)).collect()
+            }),
             encoders: Mutex::new(encoders),
             gtt: Mutex::new(gtt),
             ring: Mutex::new(ring),
@@ -715,6 +718,37 @@ impl GpuDriver for AmdDriver {
 
         Ok(None)
     }
+
+    fn set_property(&self, obj_id: u32, prop_id: u32, value: u64) -> Result<()> {
+        const CONN_PROP_DPMS: u32 = 31;
+        const DRM_MODE_DPMS_ON: i32 = 0;
+        const DRM_MODE_DPMS_OFF: i32 = 3;
+
+        if prop_id == CONN_PROP_DPMS {
+            let crtc_id = {
+                let connectors = self.connectors.lock().map_err(|_| {
+                    DriverError::Initialization("connector state poisoned".into())
+                })?;
+                connectors
+                    .iter()
+                    .find(|c| c.info.id == obj_id)
+                    .map(|c| c.info.encoder_id)
+                    .ok_or_else(|| DriverError::NotFound(format!("unknown connector {obj_id}")))?
+            };
+
+            let dpms_mode = match value {
+                0 => DRM_MODE_DPMS_ON,
+                3 => DRM_MODE_DPMS_OFF,
+                _ => return Ok(()),
+            };
+
+            return self.display.set_dpms(crtc_id, dpms_mode);
+        }
+
+        Err(DriverError::Unsupported(
+            "property not supported for this object",
+        ))
+    }
         };
 
         if !irq_event {

local/recipes/gpu/redox-drm/source/src/scheme.rs

@@ -117,6 +117,8 @@ const CRTC_PROP_MODE_ID: u32 = 21;
 
 // Connector property IDs (30-39 range)
 const CONN_PROP_CRTC_ID: u32 = 30;
+const CONN_PROP_DPMS: u32 = 31;
+const CONN_PROP_EDID: u32 = 32;
 
 const PLANE_PROPERTY_COUNT: usize = 10;
 
@@ -362,6 +364,16 @@ struct DrmModePropertyEnumWire {
     name: [u8; DRM_PROP_NAME_LEN],
 }
 
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Default)]
+struct DrmModeObjSetPropertyWire {
+    value: u64,
+    obj_id: u32,
+    obj_type: u32,
+    prop_id: u32,
+    _pad: u32,
+}
+
 #[repr(C)]
 #[derive(Clone, Copy, Debug, Default)]
 struct DrmSetClientCapWire {
@@ -1247,6 +1259,30 @@ impl DrmScheme {
 
                 out = bytes_of(&response);
             }
+            CONN_PROP_DPMS => {
+                response.flags = DRM_MODE_PROP_ATOMIC | DRM_MODE_PROP_ENUM;
+                response.count_enum_blobs = 4;
+                copy_c_string(&mut response.name, b"DPMS");
+
+                out = bytes_of(&response);
+                for (value, name) in [
+                    (0, b"On\0"),
+                    (1, b"Standby\0"),
+                    (2, b"Suspend\0"),
+                    (3, b"Off\0"),
+                ] {
+                    let mut e = DrmModePropertyEnumWire::default();
+                    e.value = value;
+                    copy_c_string(&mut e.name, name);
+                    out.extend_from_slice(&bytes_of(&e));
+                }
+            }
+            CONN_PROP_EDID => {
+                response.flags = DRM_MODE_PROP_IMMUTABLE | DRM_MODE_PROP_BLOB;
+                copy_c_string(&mut response.name, b"EDID");
+
+                out = bytes_of(&response);
+            }
             _ => out = bytes_of(&response),
         }
 
@@ -2438,7 +2474,12 @@ impl DrmScheme {
             }
 
             DRM_IOCTL_MODE_OBJ_SETPROPERTY => {
-                vec![]
+                let req = decode_wire::<DrmModeObjSetPropertyWire>(payload)?;
+                match self.driver.set_property(req.obj_id, req.prop_id, req.value) {
+                    Ok(()) => vec![],
+                    Err(DriverError::Unsupported(_)) => vec![],
+                    Err(e) => return Err(driver_to_syscall(e)),
+                }
             }
 
             0 => {