Re: [PATCH] drm/udl: Increase get urb timeout for modeset

[oushixiong]

If the wait times for all operations increase, it would likely cause 
significant blocking in the display process.
Should we make a distinction between the two, or base it on what you 
said about increasing  the regular GET_URB_TIMEOUT for all operations ?

Best regards
Shixiong
在 2025/11/5 16:57, Thomas Zimmermann 写道:
Hi

Am 05.11.25 um 09:30 schrieb oushixiong1...@163.com:
From: Shixiong Ou <oushixi...@kylinos.cn>

[WHY]
There is a situation where udl_handle_damage() was running successfully
but the screen was black. it was because 
udl_crtc_helper_atomic_enable() failed,
and there were no error messages.

[HOW]
The priority for mode settings needs to be higher than damage handle, 
requiring
a higher success rate than ordinary operations.
Increase get urb timeout for modeset.

Signed-off-by: Shixiong Ou <oushixi...@kylinos.cn>
---
  drivers/gpu/drm/udl/udl_drv.h      |  5 ++++-
  drivers/gpu/drm/udl/udl_main.c     |  5 ++---
  drivers/gpu/drm/udl/udl_modeset.c  | 11 +++++++----
  drivers/gpu/drm/udl/udl_transfer.c |  2 +-
  4 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/udl/udl_drv.h 
b/drivers/gpu/drm/udl/udl_drv.h
index 145bb95ccc48..38b3bdf1ae4a 100644
--- a/drivers/gpu/drm/udl/udl_drv.h
+++ b/drivers/gpu/drm/udl/udl_drv.h
@@ -31,6 +31,9 @@ struct drm_mode_create_dumb;
  #define DRIVER_MINOR        0
  #define DRIVER_PATCHLEVEL    1
  +#define GET_URB_TIMEOUT    HZ
+#define MODESET_GET_URB_TIMEOUT    (HZ*2)
+

Just increase the regular GET_URB_TIMEOUT for all operations.

Best regards
Thomas

  struct udl_device;
    struct urb_node {
@@ -72,7 +75,7 @@ static inline struct usb_device 
*udl_to_usb_device(struct udl_device *udl)
  int udl_modeset_init(struct udl_device *udl);
  struct drm_connector *udl_connector_init(struct drm_device *dev);
  -struct urb *udl_get_urb(struct udl_device *udl);
+struct urb *udl_get_urb(struct udl_device *udl, long timeout);
    int udl_submit_urb(struct udl_device *udl, struct urb *urb, 
size_t len);
  void udl_sync_pending_urbs(struct udl_device *udl);
diff --git a/drivers/gpu/drm/udl/udl_main.c 
b/drivers/gpu/drm/udl/udl_main.c
index bc58991a6f14..891996f0f74b 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 *udl_get_urb(struct udl_device *udl, long timeout)
  {
      struct urb *urb;
        spin_lock_irq(&udl->urbs.lock);
-    urb = udl_get_urb_locked(udl, GET_URB_TIMEOUT);
+    urb = udl_get_urb_locked(udl, timeout);
      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..6adca5e3e471 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>
  @@ -217,7 +218,7 @@ static int udl_handle_damage(struct 
drm_framebuffer *fb,
          return ret;
      log_bpp = ret;
  -    urb = udl_get_urb(udl);
+    urb = udl_get_urb(udl, GET_URB_TIMEOUT);
      if (!urb)
          return -ENOMEM;
      cmd = urb->transfer_buffer;
@@ -341,9 +342,11 @@ static void udl_crtc_helper_atomic_enable(struct 
drm_crtc *crtc, struct drm_atom
      if (!drm_dev_enter(dev, &idx))
          return;
  -    urb = udl_get_urb(udl);
-    if (!urb)
+    urb = udl_get_urb(udl, MODESET_GET_URB_TIMEOUT);
+    if (!urb) {
+        DRM_ERROR("Udl get urb failed when enabling crtc");
          goto out;
+    }
        buf = (char *)urb->transfer_buffer;
      buf = udl_vidreg_lock(buf);
@@ -374,7 +377,7 @@ static void udl_crtc_helper_atomic_disable(struct 
drm_crtc *crtc, struct drm_ato
      if (!drm_dev_enter(dev, &idx))
          return;
  -    urb = udl_get_urb(udl);
+    urb = udl_get_urb(udl, MODESET_GET_URB_TIMEOUT);
      if (!urb)
          goto out;
  diff --git a/drivers/gpu/drm/udl/udl_transfer.c 
b/drivers/gpu/drm/udl/udl_transfer.c
index 7d670b3a5293..858b47522d78 100644
--- a/drivers/gpu/drm/udl/udl_transfer.c
+++ b/drivers/gpu/drm/udl/udl_transfer.c
@@ -202,7 +202,7 @@ int udl_render_hline(struct udl_device *udl, int 
log_bpp, struct urb **urb_ptr,
              int ret = udl_submit_urb(udl, urb, len);
              if (ret)
                  return ret;
-            urb = udl_get_urb(udl);
+            urb = udl_get_urb(udl, GET_URB_TIMEOUT);
              if (!urb)
                  return -EAGAIN;
              *urb_ptr = urb;