Merge tag 'drm-misc-next-2025-04-09' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-next

drm-misc-next for v6.16-rc1:

UAPI Changes:
- Add ASAHI uapi header!
- Add apple fourcc modifiers.
- Add capset virtio definitions to UAPI.
- Extend EXPORT_SYNC_FILE for timeline syncobjs.

Cross-subsystem Changes:
- Adjust DMA-BUF sg handling to not cache map on attach.
- Update drm/ci, hlcdc, virtio, maintainers.
- Update fbdev todo.
- Allow setting dma-device for dma-buf import.
- Export efi_mem_desc_lookup to make efidrm build as a module.

Core Changes:
- Update drm scheduler docs.
- Use the correct resv object in TTM delayed destroy.
- Fix compiler warning with panic qr code, and other small fixes.
- drm/ci updates.
- Add debugfs file for listing all bridges.
- Small fixes to drm/client, ttm tests.
- Add documentation to display/hdmi.
- Add kunit tests for bridges.
- Dont fail managed device probing if connector polling fails.
- Create Kconfig.debug for drm core.
- Add tests for the drm scheduler.
- Add and use new access helpers for DPCPD.
- Add generic and optimized conversions for format-helper.
- Begin refcounting panel for improving lifetime handling.
- Unify simpledrm and ofdrm sysfb, and add extra features.
- Split hdmi audio in bridge to make DP audio work.

Driver Changes:
- Convert drivers to use devm_platform_ioremap_resource().
- Assorted small fixes to imx/legacy-bridg, gma500, pl111, nouveau, vc4,
  vmwgfx, ast, mxsfb, xlnx, accel/qaic, v3d, bridge/imx8qxp-ldb, ofdrm,
  bridge/fsl-ldb, udl, bridge/ti-sn65dsi86, bridge/anx7625, cirrus-qemu,
  bridge/cdns-dsi, panel/sharp, panel/himax, bridge/sil902x, renesas,
  imagination, various panels.
- Allow attaching more display to vkms.
- Add Powertip PH128800T004-ZZA01 panel.
- Add rotation quirk for ZOTAC panel.
- Convert bridge/tc358775 to atomic.
- Remove deprecated panel calls from synaptics, novatek, samsung panels.
- Refactor shmem helper page pinning and accel drivers using it.
- Add dmabuf support to accel/amdxdna.
- Use 4k page table format for panfrost/mediatek.
- Add common powerup/down dp link helper and use it.
- Assorted compiler warning fixes.
- Support dma-buf import for renesas

Signed-off-by: Dave Airlie <airlied@redhat.com>

# Conflicts:
#	include/drm/drm_kunit_helpers.h
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://lore.kernel.org/r/e147ff95-697b-4067-9e2e-7cbd424e162a@linux.intel.com

1 files changed, 77 insertions, 35 deletions

diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 50928a7ae98e..1a7e377d4cbb 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -383,8 +383,15 @@ struct drm_sched_job {
 	struct xarray			dependencies;
 };
 
+/**
+ * enum drm_gpu_sched_stat - the scheduler's status
+ *
+ * @DRM_GPU_SCHED_STAT_NONE: Reserved. Do not use.
+ * @DRM_GPU_SCHED_STAT_NOMINAL: Operation succeeded.
+ * @DRM_GPU_SCHED_STAT_ENODEV: Error: Device is not available anymore.
+ */
 enum drm_gpu_sched_stat {
-	DRM_GPU_SCHED_STAT_NONE, /* Reserve 0 */
+	DRM_GPU_SCHED_STAT_NONE,
 	DRM_GPU_SCHED_STAT_NOMINAL,
 	DRM_GPU_SCHED_STAT_ENODEV,
 };
@@ -410,10 +417,36 @@ struct drm_sched_backend_ops {
 					 struct drm_sched_entity *s_entity);
 
 	/**
-         * @run_job: Called to execute the job once all of the dependencies
-         * have been resolved.  This may be called multiple times, if
-	 * timedout_job() has happened and drm_sched_job_recovery()
-	 * decides to try it again.
+	 * @run_job: Called to execute the job once all of the dependencies
+	 * have been resolved.
+	 *
+	 * @sched_job: the job to run
+	 *
+	 * The deprecated drm_sched_resubmit_jobs() (called by &struct
+	 * drm_sched_backend_ops.timedout_job) can invoke this again with the
+	 * same parameters. Using this is discouraged because it violates
+	 * dma_fence rules, notably dma_fence_init() has to be called on
+	 * already initialized fences for a second time. Moreover, this is
+	 * dangerous because attempts to allocate memory might deadlock with
+	 * memory management code waiting for the reset to complete.
+	 *
+	 * TODO: Document what drivers should do / use instead.
+	 *
+	 * This method is called in a workqueue context - either from the
+	 * submit_wq the driver passed through drm_sched_init(), or, if the
+	 * driver passed NULL, a separate, ordered workqueue the scheduler
+	 * allocated.
+	 *
+	 * Note that the scheduler expects to 'inherit' its own reference to
+	 * this fence from the callback. It does not invoke an extra
+	 * dma_fence_get() on it. Consequently, this callback must take a
+	 * reference for the scheduler, and additional ones for the driver's
+	 * respective needs.
+	 *
+	 * Return:
+	 * * On success: dma_fence the driver must signal once the hardware has
+	 * completed the job ("hardware fence").
+	 * * On failure: NULL or an ERR_PTR.
 	 */
 	struct dma_fence *(*run_job)(struct drm_sched_job *sched_job);
 
@@ -421,43 +454,52 @@ struct drm_sched_backend_ops {
 	 * @timedout_job: Called when a job has taken too long to execute,
 	 * to trigger GPU recovery.
 	 *
-	 * This method is called in a workqueue context.
+	 * @sched_job: The job that has timed out
+	 *
+	 * Drivers typically issue a reset to recover from GPU hangs.
+	 * This procedure looks very different depending on whether a firmware
+	 * or a hardware scheduler is being used.
+	 *
+	 * For a FIRMWARE SCHEDULER, each ring has one scheduler, and each
+	 * scheduler has one entity. Hence, the steps taken typically look as
+	 * follows:
 	 *
-	 * Drivers typically issue a reset to recover from GPU hangs, and this
-	 * procedure usually follows the following workflow:
+	 * 1. Stop the scheduler using drm_sched_stop(). This will pause the
+	 *    scheduler workqueues and cancel the timeout work, guaranteeing
+	 *    that nothing is queued while the ring is being removed.
+	 * 2. Remove the ring. The firmware will make sure that the
+	 *    corresponding parts of the hardware are resetted, and that other
+	 *    rings are not impacted.
+	 * 3. Kill the entity and the associated scheduler.
 	 *
-	 * 1. Stop the scheduler using drm_sched_stop(). This will park the
-	 *    scheduler thread and cancel the timeout work, guaranteeing that
-	 *    nothing is queued while we reset the hardware queue
-	 * 2. Try to gracefully stop non-faulty jobs (optional)
-	 * 3. Issue a GPU reset (driver-specific)
-	 * 4. Re-submit jobs using drm_sched_resubmit_jobs()
-	 * 5. Restart the scheduler using drm_sched_start(). At that point, new
-	 *    jobs can be queued, and the scheduler thread is unblocked
+	 *
+	 * For a HARDWARE SCHEDULER, a scheduler instance schedules jobs from
+	 * one or more entities to one ring. This implies that all entities
+	 * associated with the affected scheduler cannot be torn down, because
+	 * this would effectively also affect innocent userspace processes which
+	 * did not submit faulty jobs (for example).
+	 *
+	 * Consequently, the procedure to recover with a hardware scheduler
+	 * should look like this:
+	 *
+	 * 1. Stop all schedulers impacted by the reset using drm_sched_stop().
+	 * 2. Kill the entity the faulty job stems from.
+	 * 3. Issue a GPU reset on all faulty rings (driver-specific).
+	 * 4. Re-submit jobs on all schedulers impacted by re-submitting them to
+	 *    the entities which are still alive.
+	 * 5. Restart all schedulers that were stopped in step #1 using
+	 *    drm_sched_start().
 	 *
 	 * Note that some GPUs have distinct hardware queues but need to reset
 	 * the GPU globally, which requires extra synchronization between the
-	 * timeout handler of the different &drm_gpu_scheduler. One way to
-	 * achieve this synchronization is to create an ordered workqueue
-	 * (using alloc_ordered_workqueue()) at the driver level, and pass this
-	 * queue to drm_sched_init(), to guarantee that timeout handlers are
-	 * executed sequentially. The above workflow needs to be slightly
-	 * adjusted in that case:
-	 *
-	 * 1. Stop all schedulers impacted by the reset using drm_sched_stop()
-	 * 2. Try to gracefully stop non-faulty jobs on all queues impacted by
-	 *    the reset (optional)
-	 * 3. Issue a GPU reset on all faulty queues (driver-specific)
-	 * 4. Re-submit jobs on all schedulers impacted by the reset using
-	 *    drm_sched_resubmit_jobs()
-	 * 5. Restart all schedulers that were stopped in step #1 using
-	 *    drm_sched_start()
+	 * timeout handlers of different schedulers. One way to achieve this
+	 * synchronization is to create an ordered workqueue (using
+	 * alloc_ordered_workqueue()) at the driver level, and pass this queue
+	 * as drm_sched_init()'s @timeout_wq parameter. This will guarantee
+	 * that timeout handlers are executed sequentially.
 	 *
-	 * Return DRM_GPU_SCHED_STAT_NOMINAL, when all is normal,
-	 * and the underlying driver has started or completed recovery.
+	 * Return: The scheduler's status, defined by &enum drm_gpu_sched_stat
 	 *
-	 * Return DRM_GPU_SCHED_STAT_ENODEV, if the device is no longer
-	 * available, i.e. has been unplugged.
 	 */
 	enum drm_gpu_sched_stat (*timedout_job)(struct drm_sched_job *sched_job);