Hi Hans,
On 12/18/2010 12:31 PM, Hans Verkuil wrote:
Hi all,
Now that the BKL patch series has been merged in 2.6.37 it is time to work
on replacing .ioctl by .unlocked_ioctl in all v4l drivers.
I've made an inventory of all drivers that still use .ioctl and I am looking
for volunteers to tackle one or more drivers.
I have CCed this email to the maintainers of the various drivers (if I know
who it is) in the hope that we can get this conversion done as quickly as
possible.
If I have added your name to a driver, then please confirm if you are able to
work on it or not. If you can't work on it, but you know someone else, then
let me know as well.
There is also a list of drivers where I do not know who can do the conversion.
If you can tackle one or more of those, please respond. Unfortunately, those
are among the hardest to convert :-(
It would be great if we can tackle most of these drivers for 2.6.38. I think
we should finish all drivers for 2.6.39 at the latest.
There are two ways of doing the conversion: one is to do all the locking within
the driver, the other is to use core-assisted locking. How to do the core-assisted
locking is described in Documentation/video4linux/v4l2-framework.txt, but I'll
repeat the relevant part here:
v4l2_file_operations and locking
--------------------------------
You can set a pointer to a mutex_lock in struct video_device. Usually this
will be either a top-level mutex or a mutex per device node. If you want
finer-grained locking then you have to set it to NULL and do you own locking.
If a lock is specified then all file operations will be serialized on that
lock. If you use videobuf then you must pass the same lock to the videobuf
queue initialize function: if videobuf has to wait for a frame to arrive, then
it will temporarily unlock the lock and relock it afterwards. If your driver
also waits in the code, then you should do the same to allow other processes
to access the device node while the first process is waiting for something.
The implementation of a hotplug disconnect should also take the lock before
calling v4l2_device_disconnect.
Driver list:
saa7146 (Hans Verkuil)
mem2mem_testdev (Pawel Osciak or Marek Szyprowski)
cx23885 (Steve Toth)
cx18-alsa (Andy Walls)
omap24xxcam (Sakari Ailus or David Cohen)
au0828 (Janne Grunau)
cpia2 (Andy Walls or Hans Verkuil)
cx231xx (Mauro Carvalho Chehab)
davinci (Muralidharan Karicheri)
saa6588 (Hans Verkuil)
pvrusb2 (Mike Isely)
usbvision (Hans Verkuil)
s5p-fimc (Sylwester Nawrocki)
I've done a conversion of s5p-fimc already. The relevant patch
is included in my last pull request of the driver bugfix changeset
for 2.6.37.
I am not sure what are Mauro's plans about this changeset, I hope it is
not too late to have it in 2.6.37. If it is, then it would be good to
pick up at least the commit
7db545a [media] s5p-fimc: BKL lock removal - compilation fix
because without it the driver is not even compiling. The above commit
fixes some integration problem, i.e. I submitted the camera capture
support patches and in parallel there were changes in the v4l core.
Then I have also prepared further patch converting from driver's own
to the core assisted locking, but it's on my queue for 2.6.38.
That was submitted together with the videobuf 2 patches
http://git.infradead.org/users/kmpark/linux-2.6-samsung/shortlog/refs/heads/vb2-mfc-fimc
fsl-viu (Anatolij Gustschin)
tlg2300 (Mauro Carvalho Chehab)
zr364xx (Hans de Goede)
soc_camera (Guennadi Liakhovetski)
usbvideo/vicam (Hans de Goede)
s2255drv (Pete Eberlein)
bttv (Mauro Carvalho Chehab)
stk-webcam (Hans de Goede)
se401 (Hans de Goede)
si4713-i2c (Hans Verkuil)
dsbr100 (Hans Verkuil)
Staging driver list:
go7007 (Pete Eberlein)
tm6000 (Mauro Carvalho Chehab)
(stradis/cpia: will be removed in 2.6.38, so no need to do anything)
Unassigned drivers:
saa7134
I could try converting saa7134 in my spare time, but it is rather
a huge driver and I have no experience with it.
If there is really nobody more familiar to take care of it I would
try it.
I have avermedia E506 TV card on hand, would it be enough for basic testing?
snawrocki@thinkpad:~/linux/v4l-dvb$ sudo lspci -vv
16:00.0 Multimedia controller: Philips Semiconductors
SAA7131/SAA7133/SAA7135 Video Broadcast Decoder (rev d1)
Subsystem: Avermedia Technologies Inc Device f436
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 64
Interrupt: pin A routed to IRQ 16
Region 0: Memory at 44000000 (32-bit, non-prefetchable) [size=2K]
Capabilities: [40] Power Management version 2
Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
Kernel driver in use: saa7134
Kernel modules: saa7134
em28xx
cx88
solo6x10 (staging driver)
Regards,
Hans
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