On 01/19/2012 06:08 PM, Mauro Carvalho Chehab wrote:
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<mche...@redhat.com>
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.. $(ls drivers/media/dvb/dvb-core/*.c|grep -v
dvb_frontend)
624f0c1 [media] dvb_ca_en50221: fix compilation breakage
58fae67 [media] DVB: dvb_net_init: return -errno on error
(I don't think those two would affect it)
You may check the logic on those and see if is there anything wrong.
If this doesn't work, then, you'll can use git bisect, in order to identify
the exact patch that broke it. A git bisect between 3.2 and staging/for_v3.3
should be quick, as there are "only" 715 patches. With 10 compilations
(ceil(log2(715)) = 10), you should be able to get what's wrong.
As there were no changes at the media-build backport patches, you can
even do the bisect there, speeding up your compilation time.
Problem found. Bisecting was easier that I guessed :)
commit b9d5efcceb6b34ee20111b62cf7be61ae79af4e9
Author: Andreas Oberritter <o...@linuxtv.org>
Date: Fri Dec 9 21:37:00 2011 -0300
[media] DVB: dvb_frontend: fix delayed thread exit
[crope@localhost linux]$ git bisect bad
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[b9d5efcceb6b34ee20111b62cf7be61ae79af4e9] [media] DVB: dvb_frontend:
fix delayed thread exit
[crope@localhost linux]$
[crope@localhost linux]$ git bisect log
git bisect start
# good: [805a6af8dba5dfdd35ec35dc52ec0122400b2610] Linux 3.2
git bisect good 805a6af8dba5dfdd35ec35dc52ec0122400b2610
# bad: [224a37de9f12780d45ca590fa7a625fbbb68b172] cxd2820r: fix
dvb_frontend_ops
git bisect bad 224a37de9f12780d45ca590fa7a625fbbb68b172
# bad: [1ac6a854ad444680bffbacd9e340e40c75adc367] [media] cx24116:
report delivery system and cleanups
git bisect bad 1ac6a854ad444680bffbacd9e340e40c75adc367
# good: [8159c184cf58ac78fc868d776fa2062d1162b6e5] [media] tm6000:
bugfix at interrupt reset
git bisect good 8159c184cf58ac78fc868d776fa2062d1162b6e5
# good: [5f0a6e2d503896062f641639dacfe5055c2f593b] Linux 3.2-rc7
git bisect good 5f0a6e2d503896062f641639dacfe5055c2f593b
# good: [12ba77ee7b393dacfd8f71aaa9be8184b81e39ea] [media] m5mols:
Change auto exposure control default value to AUTO
git bisect good 12ba77ee7b393dacfd8f71aaa9be8184b81e39ea
# bad: [67ccfe3b9ed5287363d01820a06e18f9376d3802] [media] tda18218: use
DVBv5 parameters on set_params()
git bisect bad 67ccfe3b9ed5287363d01820a06e18f9376d3802
# good: [a1dca1e30ac7991d8a90a3377008c850eb466edf] [media] [saa7134] do
not change mute state for capturing audio
git bisect good a1dca1e30ac7991d8a90a3377008c850eb466edf
# bad: [7b0962d32362a0d56627a1dfdb4e8229c5f51f94] [media] cx88-dvb avoid
dangling core->gate_ctrl pointer
git bisect bad 7b0962d32362a0d56627a1dfdb4e8229c5f51f94
# bad: [1b7acf0ccd61b814032668d1d21740cfae3304e3] [media] xc4000: Use
kcalloc instead of kzalloc to allocate array
git bisect bad 1b7acf0ccd61b814032668d1d21740cfae3304e3
# bad: [505b534d9611023a5fcd6010c4366d5cb884d751] [media] v4l: s5p-tv:
Use kcalloc instead of kzalloc to allocate array
git bisect bad 505b534d9611023a5fcd6010c4366d5cb884d751
[crope@localhost linux]$
[crope@localhost linux]$ git show b9d5efcceb6b34ee20111b62cf7be61ae79af4e9
commit b9d5efcceb6b34ee20111b62cf7be61ae79af4e9
Author: Andreas Oberritter <o...@linuxtv.org>
Date: Fri Dec 9 21:37:00 2011 -0300
[media] DVB: dvb_frontend: fix delayed thread exit
There are some issues and miss-behaves at the dvb fe thread:
1) dvb_shutdown_timeout should be dvb_shutdown_timeout * HZ
instead of (dvb_shutdown_timeout * HZ + 1);
2) add a memory barrier to warrant that all CPU's will consider the
new value for release_jiffies;
3) wake up dvb thread also when fepriv->exit == DVB_FE_NO_EXIT.
Signed-off-by: Andreas Oberritter <o...@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mche...@redhat.com>
diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c
b/drivers/media/dvb/dvb-core/dvb_frontend.c
index 66537b1..3ff37cf 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -507,7 +507,7 @@ static int dvb_frontend_is_exiting(struct
dvb_frontend *fe)
return 1;
if (fepriv->dvbdev->writers == 1)
- if (time_after(jiffies, fepriv->release_jiffies +
+ if (time_after_eq(jiffies, fepriv->release_jiffies +
dvb_shutdown_timeout * HZ))
return 1;
@@ -2116,12 +2116,15 @@ static int dvb_frontend_release(struct inode
*inode, struct file *file)
dprintk ("%s\n", __func__);
- if ((file->f_flags & O_ACCMODE) != O_RDONLY)
+ if ((file->f_flags & O_ACCMODE) != O_RDONLY) {
fepriv->release_jiffies = jiffies;
+ mb();
+ }
ret = dvb_generic_release (inode, file);
if (dvbdev->users == -1) {
+ wake_up(&fepriv->wait_queue);
if (fepriv->exit != DVB_FE_NO_EXIT) {
fops_put(file->f_op);
file->f_op = NULL;
[crope@localhost linux]$
--
http://palosaari.fi/
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