From 7dbdd9018603c417a64736414262a4e9b6203390 Mon Sep 17 00:00:00 2001 From: Frank Schaefer Date: Sat, 9 Aug 2014 06:37:20 -0300 Subject: [PATCH] media: em28xx-v4l: give back all active video buffers to the vb2 core properly on streaming stop MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 627530c32a43283474e9dd3e954519410ffa033a upstream. When a new video frame is started, the driver takes the next video buffer from the list of active buffers and moves it to dev->usb_ctl.vid_buf / dev->usb_ctl.vbi_buf for further processing. On streaming stop we currently only give back the pending buffers from the list but not the ones which are currently processed. This causes the following warning from the vb2 core since kernel 3.15: ... ------------[ cut here ]------------ WARNING: CPU: 1 PID: 2284 at drivers/media/v4l2-core/videobuf2-core.c:2115 __vb2_queue_cancel+0xed/0x150 [videobuf2_core]() [...] Call Trace: [] dump_stack+0x48/0x69 [] warn_slowpath_common+0x79/0x90 [] ? __vb2_queue_cancel+0xed/0x150 [videobuf2_core] [] ? __vb2_queue_cancel+0xed/0x150 [videobuf2_core] [] warn_slowpath_null+0x1d/0x20 [] __vb2_queue_cancel+0xed/0x150 [videobuf2_core] [] vb2_internal_streamoff+0x35/0x90 [videobuf2_core] [] vb2_streamoff+0x35/0x60 [videobuf2_core] [] vb2_ioctl_streamoff+0x37/0x40 [videobuf2_core] [] v4l_streamoff+0x15/0x20 [videodev] [] __video_do_ioctl+0x23d/0x2d0 [videodev] [] ? video_ioctl2+0x20/0x20 [videodev] [] video_usercopy+0x203/0x5a0 [videodev] [] ? video_ioctl2+0x20/0x20 [videodev] [] ? fsnotify+0x1e7/0x2b0 [] video_ioctl2+0x12/0x20 [videodev] [] ? video_ioctl2+0x20/0x20 [videodev] [] v4l2_ioctl+0xee/0x130 [videodev] [] ? v4l2_open+0xf0/0xf0 [videodev] [] do_vfs_ioctl+0x2e2/0x4d0 [] ? vfs_write+0x13c/0x1c0 [] ? vfs_writev+0x2f/0x50 [] SyS_ioctl+0x58/0x80 [] sysenter_do_call+0x12/0x12 ---[ end trace 5545f934409f13f4 ]--- ... Many thanks to Hans Verkuil, whose recently added check in the vb2 core unveiled this long standing issue and who has investigated it further. Signed-off-by: Frank Schäfer Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/em28xx/em28xx-video.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c index 32d60e5..a2737b4 100644 --- a/drivers/media/usb/em28xx/em28xx-video.c +++ b/drivers/media/usb/em28xx/em28xx-video.c @@ -696,13 +696,16 @@ static int em28xx_stop_streaming(struct vb2_queue *vq) } spin_lock_irqsave(&dev->slock, flags); + if (dev->usb_ctl.vid_buf != NULL) { + vb2_buffer_done(&dev->usb_ctl.vid_buf->vb, VB2_BUF_STATE_ERROR); + dev->usb_ctl.vid_buf = NULL; + } while (!list_empty(&vidq->active)) { struct em28xx_buffer *buf; buf = list_entry(vidq->active.next, struct em28xx_buffer, list); list_del(&buf->list); vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR); } - dev->usb_ctl.vid_buf = NULL; spin_unlock_irqrestore(&dev->slock, flags); return 0; @@ -724,13 +727,16 @@ int em28xx_stop_vbi_streaming(struct vb2_queue *vq) } spin_lock_irqsave(&dev->slock, flags); + if (dev->usb_ctl.vbi_buf != NULL) { + vb2_buffer_done(&dev->usb_ctl.vbi_buf->vb, VB2_BUF_STATE_ERROR); + dev->usb_ctl.vbi_buf = NULL; + } while (!list_empty(&vbiq->active)) { struct em28xx_buffer *buf; buf = list_entry(vbiq->active.next, struct em28xx_buffer, list); list_del(&buf->list); vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR); } - dev->usb_ctl.vbi_buf = NULL; spin_unlock_irqrestore(&dev->slock, flags); return 0; -- 2.7.4