On 06/02/2015 09:07 PM, Laura Abbott wrote:
> Currently, the warning for missing device_caps gives a backtrace like so:
>
> [] dump_stack+0x45/0x57
> [] warn_slowpath_common+0x8a/0xc0
> [] warn_slowpath_null+0x1a/0x20
> [] v4l_querycap+0x43/0x80 [videodev]
> [] __video_do_ioctl+0x2a4/0x320 [videodev]
> [] ? do_last+0x195/0x1210
> [] video_usercopy+0x22e/0x5b0 [videodev]
> [] ? v4l_querycap+0x80/0x80 [videodev]
> [] video_ioctl2+0x15/0x20 [videodev]
> [] v4l2_ioctl+0x113/0x150 [videodev]
> [] do_vfs_ioctl+0x2f8/0x4f0
> [] ? __audit_syscall_entry+0xb4/0x110
> [] ? do_audit_syscall_entry+0x6c/0x70
> [] SyS_ioctl+0x81/0xa0
> [] ? __audit_syscall_exit+0x1f6/0x2a0
> [] system_call_fastpath+0x12/0x17
>
> This indicates that device_caps are missing but doesn't give
> much of a clue which driver is actually at fault. Improve
> the warning output by showing the capabilities and which
> operations set the capabilities.
>
> Signed-off-by: Laura Abbott
> ---
> drivers/media/v4l2-core/v4l2-ioctl.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c
> b/drivers/media/v4l2-core/v4l2-ioctl.c
> index aa407cb..e509608 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1023,8 +1023,9 @@ static int v4l_querycap(const struct v4l2_ioctl_ops
> *ops,
>* Drivers MUST fill in device_caps, so check for this and
>* warn if it was forgotten.
>*/
> - WARN_ON(!(cap->capabilities & V4L2_CAP_DEVICE_CAPS) ||
> - !cap->device_caps);
> + WARN(!(cap->capabilities & V4L2_CAP_DEVICE_CAPS) ||
> + !cap->device_caps, "Bad caps for ops %pS, %x %x",
> + ops, cap->capabilities, cap->device_caps);
Why not just print cap->driver? Much simpler and it always works!
Regards,
Hans
> cap->device_caps |= V4L2_CAP_EXT_PIX_FORMAT;
>
> return ret;
>
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