Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 17 Jul 2003 14:49:07 -0700 | From | Greg KH <> | Subject | Re: [RFC/PATCH] sysfs'ify video4linux |
| |
On Thu, Jul 17, 2003 at 06:37:15PM +0200, Gerd Knorr wrote: > > Version (1) can be done without breaking the build, with a hack along > the lines "if (no release callback) printk(KERN_WARN please fix your > driver)", so the drivers can be fixed step-by-step afterwards.
That sounds like a nice way to start.
> Fixing the drivers might be non-trivial through. Some drivers are > hot-pluggable (usb cams), some drivers register more than one v4l device > (bttv wants up to three). Those drivers can't just call kfree() in the > ->release callback because there might be other references, some open > file handle for a unplugged usb cam, another not-yet unregistered > v4l device, whatever. Probably they must implement some reference > counting scheme to get that right. The very simple ones (in > drivers/media/radio for example) likely just need the kfree() moved > from the ->remove function into the new ->release() callback.
I don't think it will be that bad for them. Just have them change the v4l device from being a structure included in their structure, into a pointer, and then create it before registering, and free it in the release() callback.
That being said, I haven't actually looked at the code to verify that this is all that is needed :)
> Version (2) needs every v4l driver touched to make it compile again. > Not sure how hard it is to fixup them. I'd guess it is pretty straigt > forward to do the conversion, it's just alot of work. I also could do > a number of other cleanups along the way. Maybe I trap into some hidden > pitfalls through, havn't looked at all the drivers in detail yet.
Breaking the build is a very good thing to do at times, to ensure that stuff gets fixed properly. Users might go for a while without realizing that there really is a problem in their driver.
But in the end, it's up to you...
thanks,
greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| ![\](/images/icornerr.gif) |