From: Shixiong Ou <oushixiong@kylinos.cn>

[WHY]
A situation has occurred where udl_handle_damage() executed successfully
and the kernel log appears normal, but the display fails to show any output.
This is because the call to udl_get_urb() in udl_crtc_helper_atomic_enable()
failed without generating any error message.

[HOW]
1. Increase timeout of getting urb.
2. Add error messages when calling udl_get_urb() failed in
udl_crtc_helper_atomic_enable().

Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
---
v3: Remove GET_URB_TIMEOUT macro and pass 2 * HZ directly.

 drivers/gpu/drm/udl/udl_main.c    | 3 +--
 drivers/gpu/drm/udl/udl_modeset.c | 5 ++++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index bc58991a6f14..b4c23dbcf3e3 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -285,13 +285,12 @@ static struct urb *udl_get_urb_locked(struct udl_device *udl, long timeout)
 	return unode->urb;
 }
 
-#define GET_URB_TIMEOUT	HZ
 struct urb *udl_get_urb(struct udl_device *udl)
 {
 	struct urb *urb;
 
 	spin_lock_irq(&udl->urbs.lock);
-	urb = udl_get_urb_locked(udl, GET_URB_TIMEOUT);
+	urb = udl_get_urb_locked(udl, HZ * 2);
 	spin_unlock_irq(&udl->urbs.lock);
 	return urb;
 }
diff --git a/drivers/gpu/drm/udl/udl_modeset.c b/drivers/gpu/drm/udl/udl_modeset.c
index 231e829bd709..1ca073a4ecb2 100644
--- a/drivers/gpu/drm/udl/udl_modeset.c
+++ b/drivers/gpu/drm/udl/udl_modeset.c
@@ -21,6 +21,7 @@
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_gem_shmem_helper.h>
 #include <drm/drm_modeset_helper_vtables.h>
+#include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_vblank.h>
 
@@ -342,8 +343,10 @@ static void udl_crtc_helper_atomic_enable(struct drm_crtc *crtc, struct drm_atom
 		return;
 
 	urb = udl_get_urb(udl);
-	if (!urb)
+	if (!urb) {
+		drm_err_ratelimited(dev, "get urb failed when enabling crtc\n");
 		goto out;
+	}
 
 	buf = (char *)urb->transfer_buffer;
 	buf = udl_vidreg_lock(buf);
-- 
2.47.1.windows.2

Am 24.04.26 um 14:44 schrieb Shixiong Ou:
> From: Shixiong Ou <oushixiong@kylinos.cn>
>
> [WHY]
> A situation has occurred where udl_handle_damage() executed successfully
> and the kernel log appears normal, but the display fails to show any output.
> This is because the call to udl_get_urb() in udl_crtc_helper_atomic_enable()
> failed without generating any error message.
>
> [HOW]
> 1. Increase timeout of getting urb.
> 2. Add error messages when calling udl_get_urb() failed in
> udl_crtc_helper_atomic_enable().
>
> Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>

Thanks

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

Fixes: 5320918b9a87 ("drm/udl: initial UDL driver (v4)")
Cc: <stable@vger.kernel.org> # v3.4+


> ---
> v3: Remove GET_URB_TIMEOUT macro and pass 2 * HZ directly.
>
>   drivers/gpu/drm/udl/udl_main.c    | 3 +--
>   drivers/gpu/drm/udl/udl_modeset.c | 5 ++++-
>   2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
> index bc58991a6f14..b4c23dbcf3e3 100644
> --- a/drivers/gpu/drm/udl/udl_main.c
> +++ b/drivers/gpu/drm/udl/udl_main.c
> @@ -285,13 +285,12 @@ static struct urb *udl_get_urb_locked(struct udl_device *udl, long timeout)
>   	return unode->urb;
>   }
>   
> -#define GET_URB_TIMEOUT	HZ
>   struct urb *udl_get_urb(struct udl_device *udl)
>   {
>   	struct urb *urb;
>   
>   	spin_lock_irq(&udl->urbs.lock);
> -	urb = udl_get_urb_locked(udl, GET_URB_TIMEOUT);
> +	urb = udl_get_urb_locked(udl, HZ * 2);
>   	spin_unlock_irq(&udl->urbs.lock);
>   	return urb;
>   }
> diff --git a/drivers/gpu/drm/udl/udl_modeset.c b/drivers/gpu/drm/udl/udl_modeset.c
> index 231e829bd709..1ca073a4ecb2 100644
> --- a/drivers/gpu/drm/udl/udl_modeset.c
> +++ b/drivers/gpu/drm/udl/udl_modeset.c
> @@ -21,6 +21,7 @@
>   #include <drm/drm_gem_framebuffer_helper.h>
>   #include <drm/drm_gem_shmem_helper.h>
>   #include <drm/drm_modeset_helper_vtables.h>
> +#include <drm/drm_print.h>
>   #include <drm/drm_probe_helper.h>
>   #include <drm/drm_vblank.h>
>   
> @@ -342,8 +343,10 @@ static void udl_crtc_helper_atomic_enable(struct drm_crtc *crtc, struct drm_atom
>   		return;
>   
>   	urb = udl_get_urb(udl);
> -	if (!urb)
> +	if (!urb) {
> +		drm_err_ratelimited(dev, "get urb failed when enabling crtc\n");
>   		goto out;
> +	}
>   
>   	buf = (char *)urb->transfer_buffer;
>   	buf = udl_vidreg_lock(buf);

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)