Em 19-01-2012 13:53, Antti Palosaari escreveu: > On 01/19/2012 03:31 PM, Mauro Carvalho Chehab wrote: >> Em 19-01-2012 09:57, Antti Palosaari escreveu: >>> On 01/19/2012 01:33 PM, Mauro Carvalho Chehab wrote: >>>> Em 18-01-2012 20:05, Antti Palosaari escreveu: >>>>> I tested almost all DVB-T/T2/C devices I have and all seems to be working, excluding Anysee models when using legacy zap. >>>>> >>>>> Anysee anysee_streaming_ctrl() will fail because mutex_lock_interruptible() returns -EINTR in anysee_ctrl_msg() function when zap is killed using ctrl+c. This will led error returned to DVB-USB-core and log writing "dvb-usb: error while stopping stream." >>>>> >>>>> http://git.linuxtv.org/media_tree.git/blob/refs/heads/master:/drivers/media/dvb/dvb-usb/anysee.c >>>>> >>>>> http://git.linuxtv.org/media_tree.git/blob/refs/heads/master:/drivers/media/dvb/dvb-usb/dvb-usb-urb.c >>>>> >>>>> If I change mutex_lock_interruptible() => mutex_lock() it will work. I think it gets SIGINT (ctrl+c) from userland, but how this haven't been issue earlier? >>>>> >>>>> Anyone have idea what's wrong/reason here? >>>> >>>> No idea. That part of the code wasn't changed recently, AFAIK, and >>>> for sure it weren't affected by the frontend changes. >>>> >>>> I suspect that the bug was already there, but it weren't noticed >>>> before. >>> >>> Yeah, that's what I suspect too. But it still looks weird since DVB USB generic >>> dvb_usb_generic_rw() function uses same mutex logic and it is very widely used >>> about all DVB USB drivers. The reason Anysee driver have own mutex is weird USB >>> message sequence that is 1xSEND 2xRECEIVE, instead normal 1xSEND 1xRECEIVE. >> >> I think that this is a sort of race issue: as you're taking more time at anysee, >> it is more likely to receive the break while stopping the stream. > > I installed latest 3.2.1 Kernel and no that error seen so it is regression. > Linux localhost.localdomain 3.2.1 #1 SMP Thu Jan 19 16:07:04 EET 2012 x86_64 x86_64 x86_64 GNU/Linux Maybe, but it can still be some race condition. The error is at the dmx part, so it is very unlikely that the frontend changes would cause any harm. > Hardware does not stop streaming since streaming command is newer send - > it is mutex protecting control messages that returns EINTR and command was terminated before it happens. > > >>> I did skeleton code below clear the issue. >>> >>> dvb_usb_generic_rw() {q >>> if ((ret = mutex_lock_interruptible(&d->usb_mutex))) >>> return ret; >>> >>> usb_bulk_msg(SEND BULK USB MESSAGE); >>> usb_bulk_msg(RECEIVE BULK USB MESSAGE); >>> >>> mutex_unlock(&d->usb_mutex); >>> } >>> >>> anysee_ctrl_msg() { >>> if (mutex_lock_interruptible(&anysee_usb_mutex)< 0) >>> return -EAGAIN; >>> >>> dvb_usb_generic_rw(); >>> usb_bulk_msg(RECEIVE BULK USB MESSAGE); // really! >>> >>> mutex_unlock(&anysee_usb_mutex); >>> } >>> >>> >>>> >>>> The fix seems to be as simple as: >>>> >>>> diff --git a/drivers/media/dvb/dvb-usb/dvb-usb-dvb.c b/drivers/media/dvb/dvb-usb/dvb-usb-dvb.c >>>> index ddf282f..6e707b5 100644 >>>> --- a/drivers/media/dvb/dvb-usb/dvb-usb-dvb.c >>>> +++ b/drivers/media/dvb/dvb-usb/dvb-usb-dvb.c >>>> @@ -32,7 +32,8 @@ static int dvb_usb_ctrl_feed(struct dvb_demux_feed *dvbdmxfeed, int onoff) >>>> if (adap->props.fe[adap->active_fe].streaming_ctrl != NULL) { >>>> ret = adap->props.fe[adap->active_fe].streaming_ctrl(adap, 0); >>>> if (ret< 0) { >>>> - err("error while stopping stream."); >>>> + if (ret != -EAGAIN) >>>> + err("error while stopping stream."); >>>> return ret; >>>> } >>>> } >>>> >>>> And make sure to remap -EINTR as -EAGAIN, leaving to the >>>> userspace to retry it. Alternatively, the dvb frontend core >>>> or the anysee could retry it after a while for streaming >>>> stop. >>>> >>>> Another alternative that would likely work better would >>>> be to just use mutex_lock() for streaming stop, but this >>>> would require the review of all implementations for >>>> streaming_ctrl >>> >>> I think some changes for DVB USB are needed because after .streaming_ctrl() >>> fail it will not stream anything later attempts until device is re-plugged. >>> Having this kind of effect in case of single driver callback failure is not acceptable. >> >> After thinking a little about it, I think that the best thing to do here is to >> retry automatically, like the enclosed patch. >> >> The patch doesn't take into account the device mode. If it were opened >> in non-block mode, the right behaviour would likely to return -EAGAIN, >> and let userspace to retry it. >> >>> regards >>> Antti >> >> [PATCH] dvb-usb: Don't abort stop on -EAGAIN/-EINTR >> >> Note: this patch is not complete. if the DVB demux device is opened on >> block mode, it should instead be returning -EAGAIN. >> >> Signed-off-by: Mauro Carvalho Chehab<mchehab@xxxxxxxxxx> >> >> diff --git a/drivers/media/dvb/dvb-usb/dvb-usb-dvb.c b/drivers/media/dvb/dvb-usb/dvb-usb-dvb.c >> index ddf282f..215ce75 100644 >> --- a/drivers/media/dvb/dvb-usb/dvb-usb-dvb.c >> +++ b/drivers/media/dvb/dvb-usb/dvb-usb-dvb.c >> @@ -30,7 +30,9 @@ static int dvb_usb_ctrl_feed(struct dvb_demux_feed *dvbdmxfeed, int onoff) >> usb_urb_kill(&adap->fe_adap[adap->active_fe].stream); >> >> if (adap->props.fe[adap->active_fe].streaming_ctrl != NULL) { >> - ret = adap->props.fe[adap->active_fe].streaming_ctrl(adap, 0); >> + do { >> + ret = adap->props.fe[adap->active_fe].streaming_ctrl(adap, 0); >> + } while ((ret == -EAGAIN) || (ret == -EINTR)); >> if (ret< 0) { >> err("error while stopping stream."); >> return ret; >> >> -- > > I have no knowledge which is correct and which is not. But as this is regression problem I wish to know actual reason until code changes are done. > > I compiled latest 3.1.10 and 3.2.1 vanilla Kernels form kernel.org and those worked as expected. There are just a few patches left, if we exclude the dvb_frontend changes: $ git log --oneline v3.2.. drivers/media/dvb/dvb-usb/anysee.c faf2797 [media] anysee: do not attach same frontend twice fda23fa [media] cxd2820r: switch to .get_if_frequency() 8f4ffb1 [media] anysee: fix style issues 4048da2 [media] anysee: add control message debugs 05cd37d [media] anysee: CI/CAM support be94351 [media] anysee: I2C gate control DNOD44CDH086A tuner module 608add8 [media] anysee: add support for Anysee E7 T2C (maybe some of the above caused some delay increase at anysee_streaming_ctrl()? $ git log --oneline v3.2.. $(ls drivers/media/dvb/dvb-core/*.c|grep -v dvb_frontend) 624f0c1 [media] dvb_ca_en50221: fix compilation breakage 58fae67 [media] DVB: dvb_net_init: return -errno on error (I don't think those two would affect it) You may check the logic on those and see if is there anything wrong. If this doesn't work, then, you'll can use git bisect, in order to identify the exact patch that broke it. A git bisect between 3.2 and staging/for_v3.3 should be quick, as there are "only" 715 patches. With 10 compilations (ceil(log2(715)) = 10), you should be able to get what's wrong. As there were no changes at the media-build backport patches, you can even do the bisect there, speeding up your compilation time. Regards, Mauro. > > regards > Antti -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
