Currently, the warning for missing device_caps gives a backtrace like so: [<ffffffff8175c199>] dump_stack+0x45/0x57 [<ffffffff8109ad5a>] warn_slowpath_common+0x8a/0xc0 [<ffffffff8109ae8a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa0237453>] v4l_querycap+0x43/0x80 [videodev] [<ffffffffa0237734>] __video_do_ioctl+0x2a4/0x320 [videodev] [<ffffffff812207e5>] ? do_last+0x195/0x1210 [<ffffffffa023a11e>] video_usercopy+0x22e/0x5b0 [videodev] [<ffffffffa0237490>] ? v4l_querycap+0x80/0x80 [videodev] [<ffffffffa023a4b5>] video_ioctl2+0x15/0x20 [videodev] [<ffffffffa0233733>] v4l2_ioctl+0x113/0x150 [videodev] [<ffffffff81225798>] do_vfs_ioctl+0x2f8/0x4f0 [<ffffffff8113b2d4>] ? __audit_syscall_entry+0xb4/0x110 [<ffffffff81022d7c>] ? do_audit_syscall_entry+0x6c/0x70 [<ffffffff81225a11>] SyS_ioctl+0x81/0xa0 [<ffffffff8113b526>] ? __audit_syscall_exit+0x1f6/0x2a0 [<ffffffff81763549>] 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 <labbott@xxxxxxxxxxxxxxxxx> --- 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); cap->device_caps |= V4L2_CAP_EXT_PIX_FORMAT; return ret; -- 2.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
