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

[oushixiong <oushixiong1025@163.com>]

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 oushixiong1025@163.com:
>> From: Shixiong Ou <oushixiong@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 <oushixiong@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;
>