Bug 31962
| Summary: | cx88-blackbird broken (since 2.6.37 ?) | ||
|---|---|---|---|
| Product: | v4l-dvb | Reporter: | Andi Huber (hobrom) |
| Component: | cx88 | Assignee: | v4l-dvb_cx88 |
| Status: | CLOSED CODE_FIX | ||
| Severity: | high | CC: | andrew.walker27, damoxc, florian, jrnieder, mchehab, whiteulver |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 2.6.38 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: |
patch that fixes cx88_blackbird driver lock issues
patch from http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/31187 |
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Description
Andi Huber
2011-03-27 16:09:39 UTC
Thanks. LKML thread: http://thread.gmane.org/gmane.linux.kernel/1118815 Created attachment 52902 [details]
patch that fixes cx88_blackbird driver lock issues
Ben Hutchings provided me with a patch that solved the deadlock during mpeg_open() but left some other lock issues unresolved.
I could do the remaining work and fixed all issues I had since kernel 2.6.37. (Tested on a PC with 2 Hauppauge HVR1300 TV cards.)
Everything works fine for me now.
The new patch (cx88-2.6.38-fix-driver-deadlocks.patch) is attached ...
I know this isn't a help forum but I wanted to see if this patch works but I'm not sure how to use the patch. I tried this patch cx88-blackbird.c /home/fred/cx88-2.6.38-fix-driver-deadlocks.patch but it didn't work. Am I doing this wrong? (In reply to comment #3) > I know this isn't a help forum but I wanted to see if this patch works but > I'm > not sure how to use the patch. > I tried this > > patch cx88-blackbird.c /home/fred/cx88-2.6.38-fix-driver-deadlocks.patch > > but it didn't work. Am I doing this wrong? Hi Andrew, you need to patch the kernel sources. If you have extracted them into a folder let's say /usr/src/linux-source-2.6.38/ change dir into this folder and execute patch -p1 < /home/fred/cx88-2.6.38-fix-driver-deadlocks.patch This should work. Andi. I tried patching but I get an error saying it was previously patched, I'm running Gentoo so maybe the patch is already installed. I'm wondering if I actually have the same bug as everyone here. The problem I have is no channels actually get detected on either my HVR-1300 or WinTV Nova-T although it goes through the motions without any errors. Is this associated with this bug or a different issue completely? You could try the patch in comment #147 from https://bugs.launchpad.net/mythtv/+bug/439163 with regards to that. Hi Damien, Damien Churchill wrote: > You could try the patch in comment #147 from > https://bugs.launchpad.net/mythtv/+bug/439163 with regards to that. The launchpad bug you reference seems to be about something else. (1) It is from 2009-09-29, way before the BKL conversion (2) It is about a card being recognized incorrectly rather than hangs. Are you sure you have the right bug? If so, have you tried the patches at [1] (which seem to work ok)? Naturally I'd be very interested in problems with in the patch series (regressions or locking problems the patch missed). [1] http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/31187 (In reply to comment #7) > Are you sure you have the right bug? If so, have you tried the > patches at [1] (which seem to work ok)? Naturally I'd be very > interested in problems with in the patch series (regressions or > locking problems the patch missed). > Sorry I was replying to the person above me, I should have made that clearer. He has the same card as I do and seems to experience a similar issue to me (no channels being found) and I discovered that patch whilst hunting around earlier. I was also experiencing this bug until I applied the attached patch and it has successfully fixed it so can confirm the patch works well on a Hauppauge HVR1300. Created attachment 53722 [details] patch from http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/31187 Ah, thanks, Damien. I'm attaching a patch that squashes together the fixes from http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/31187 for convenience. It's almost the same as Andi's patch but closes a few more races and keeps the reference count as a reference count to avoid breaking when multiple dvb frontends try concurrently to access the device. The no-channels-found problem is probably somehow related to <https://bugzilla.kernel.org/show_bug.cgi?id=26962>. Excellent, I'll have to rebuild and give your patch a try. I can say that removing the 4 lines as suggested in the Launchpad link (comment 147) does actually allow w_scan, scan and gstreamer all to work with my card now which is a definite improvement. Not having looked at the code I have no idea if it's a bad fix however. Comment on attachment 52902 [details] patch that fixes cx88_blackbird driver lock issues premature and replaced by https://bugzilla.kernel.org/attachment.cgi?id=53722 This and related problems should be fixed by
- 8a317a87 ([media] cx88: protect per-device driver list with device lock)
- 1fe70e96 ([media] cx88: fix locking of sub-driver operations)
- 1d6213ab ([media] cx88: hold device lock during sub-driver initialization)
- 344d6c6b ([media] cx88: protect cx8802_devlist with a mutex)
- 579b2b45 ([media] cx88: gracefully reject attempts to use unregistered
cx88-blackbird driver)
- f4bd4be8 ([media] cx88: don't use atomic_t for core->mpeg_users)
which have hit mainline (hoorah!). For the sake of people using old kernels: the regression was probably introduced in v2.6.37-rc1~64^2~350 (V4L/DVB: cx88: Remove BKL, 2010-09-15) or thereabouts (BKL removal). Anything older than that should be okay.
Many thanks to Jonathan! I'm closing this bugreport. A patch referencing this bug report has been merged in v3.0-rc1: commit 1fe70e963028f34ba5e32488a7870ff4b410b19b Author: Jonathan Nieder <jrnieder@gmail.com> Date: Sun May 1 06:29:37 2011 -0300 [media] cx88: fix locking of sub-driver operations So in which kernel version will be fixed? 2.6.39? (In reply to comment #15) > So in which kernel version will be fixed? 2.6.39? Both 2.6.38 and 2.6.39 got the fix: http://lwn.net/Articles/445974/ http://lwn.net/Articles/445972/ |