Patch "drm/nouveau: don't attempt to schedule hpd_work on headless cards" has been added to the 6.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/nouveau: don't attempt to schedule hpd_work on headless cards

to the 6.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-nouveau-don-t-attempt-to-schedule-hpd_work-on-he.patch
and it can be found in the queue-6.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit aff76250e5eec42356554e824ff303c4fe910ff9
Author: Vasily Khoruzhick <anarsoul@xxxxxxxxx>
Date:   Fri Jun 7 15:09:32 2024 -0700

    drm/nouveau: don't attempt to schedule hpd_work on headless cards
    
    [ Upstream commit b96a225377b6602299a03d2ce3c289b68cd41bb7 ]
    
    If the card doesn't have display hardware, hpd_work and hpd_lock are
    left uninitialized which causes BUG when attempting to schedule hpd_work
    on runtime PM resume.
    
    Fix it by adding headless flag to DRM and skip any hpd if it's set.
    
    Fixes: ae1aadb1eb8d ("nouveau: don't fail driver load if no display hw present.")
    Link: https://gitlab.freedesktop.org/drm/nouveau/-/issues/337
    Signed-off-by: Vasily Khoruzhick <anarsoul@xxxxxxxxx>
    Reviewed-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
    Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
    Link: https://patchwork.freedesktop.org/patch/msgid/20240607221032.25918-1-anarsoul@xxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/nouveau/dispnv04/disp.c b/drivers/gpu/drm/nouveau/dispnv04/disp.c
index 13705c5f14973..4b7497a8755cd 100644
--- a/drivers/gpu/drm/nouveau/dispnv04/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/disp.c
@@ -68,7 +68,7 @@ nv04_display_fini(struct drm_device *dev, bool runtime, bool suspend)
 	if (nv_two_heads(dev))
 		NVWriteCRTC(dev, 1, NV_PCRTC_INTR_EN_0, 0);
 
-	if (!runtime)
+	if (!runtime && !drm->headless)
 		cancel_work_sync(&drm->hpd_work);
 
 	if (!suspend)
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 0c3d88ad0b0ea..88151209033d5 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -2680,7 +2680,7 @@ nv50_display_fini(struct drm_device *dev, bool runtime, bool suspend)
 			nv50_mstm_fini(nouveau_encoder(encoder));
 	}
 
-	if (!runtime)
+	if (!runtime && !drm->headless)
 		cancel_work_sync(&drm->hpd_work);
 }
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c
index f28f9a8574586..60c32244211d0 100644
--- a/drivers/gpu/drm/nouveau/nouveau_display.c
+++ b/drivers/gpu/drm/nouveau/nouveau_display.c
@@ -450,6 +450,9 @@ nouveau_display_hpd_resume(struct drm_device *dev)
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
 
+	if (drm->headless)
+		return;
+
 	spin_lock_irq(&drm->hpd_lock);
 	drm->hpd_pending = ~0;
 	spin_unlock_irq(&drm->hpd_lock);
@@ -635,7 +638,7 @@ nouveau_display_fini(struct drm_device *dev, bool suspend, bool runtime)
 	}
 	drm_connector_list_iter_end(&conn_iter);
 
-	if (!runtime)
+	if (!runtime && !drm->headless)
 		cancel_work_sync(&drm->hpd_work);
 
 	drm_kms_helper_poll_disable(dev);
@@ -729,6 +732,7 @@ nouveau_display_create(struct drm_device *dev)
 		/* no display hw */
 		if (ret == -ENODEV) {
 			ret = 0;
+			drm->headless = true;
 			goto disp_create_err;
 		}
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
index e239c6bf4afa4..25fca98a20bcd 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -276,6 +276,7 @@ struct nouveau_drm {
 	/* modesetting */
 	struct nvbios vbios;
 	struct nouveau_display *display;
+	bool headless;
 	struct work_struct hpd_work;
 	spinlock_t hpd_lock;
 	u32 hpd_pending;