Commit Graph

4 Commits

Author SHA1 Message Date
Hans de Goede
844db450e6 [media] gspca: Update / fix various comments wrt workqueue usb_lock usage
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-09-13 17:52:58 -03:00
Hans de Goede
ff8f25d326 [media] gspca_finepix: Remove unnecessary lock/unlock call
gspca_main: init_transfer does not do anything between calling sd_start
(which starts the workqueue) and releasing the usb_lock, so this
synchronization is a nop, remove it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-09-13 17:44:34 -03:00
Hans de Goede
345321dc9c [media] gspca: Don't set gspca_dev->dev to NULL before stop0
In commit a3d6e8cc0e gspca_dev->dev is set
to NULL on disconnect, before calling stop0. The plan was to get rid of
gspca_dev->present and instead simply check for gspca_dev->dev everywhere
where we were checking for present. This should be race free since all users
of gspca_dev->dev hold the usb_lock, or so I thought.

But I was wrong, drivers which use a work-queue + synchronous bulk transfers
to get the video data don't hold the usb_lock while doing so, their stop0
callbacks stop the workqueue, so they won't be using gspca_dev->dev anymore
after the stop0 call, but they might be dereferincing it before, so we should
not set gspca_dev->dev to NULL on disconnect before calling stop0.

This also means that the workqueue functions in these drivers cannot
use gspca_dev->dev to check if they need to stop because of disconnection,
so we will need to keep gspca_dev->present around, and set that to 0 on
disconnect, before calling stop0. Unfortunately as part of the plan to remove
gspca_dev->present, these workqueues where already moved over to checking
for gspca_dev->dev instead of gspca_dev->present as part of commit
254902b01d, so this patch also reverts those
parts of that commit.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-09-13 17:42:17 -03:00
Mauro Carvalho Chehab
0c0d06cac6 [media] rename most media/video usb drivers to media/usb
Rename all USB drivers with their own directory under
drivers/media/video into drivers/media/usb and update the
building system.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-08-15 16:25:07 -03:00