Mauro Carvalho Chehab wrote:
Em Wed, 10 Jun 2015 18:27:30 +0100
Andy Furniss <adf.lists@xxxxxxxxx> escreveu:
Mauro Carvalho Chehab wrote:
Just applied a fix for it:
http://git.linuxtv.org/cgit.cgi/v4l-utils.git/commit/?id=c7c9af17163f282a147ea76f1a3c0e9a0a86e7fa
It will retry up to 10 times. This should very likely be enough if the
driver doesn't have any bug.
Please let me know if this fixes the issue.
No, it doesn't, so I reverted the above and added back my hack + a
counter as below and it seems to be retrying > a million times.
Hmm.... that's likely a bug at the demod driver. It doesn't make much
sense to keep a mutex hold for that long.
Anyway, I modified the patch to use a timeout of 1 second, instead of
trying 10 times. It is still a hack, as IMHO this is a driver bug,
but it should produce a better result.
Please check if the patch below works for you.
You may change the MAX_TIME there if 1 second is not enough.
It could be interesting if you add a printf with the difference
between start and end time, for us to have an idea about how
much time the driver is kept on such unreliable state.
Thanks!
Mauro
[PATCH] libdvbv5: use a timeout for ioctl
Some frontends don't play nice: they return -EAGAIN if the
device doesn't lock. That actually means that it may take
some time for some ioctl's to succeed. On experimental tests,
the loop may happen ~2 million times!
Well, better to waste power on a loop than to fail. So, let's
change the code that detects EAGAIN by a loop that waits up
to 1 second.
This is not the right thing to do, but the Kernel drivers
require fixes. We can do it only for newer versions of the
Kernel.
I can't get this to work - it instantly bails -
read_sections: read error: Resource temporarily unavailable
couldn't find pmt-pid for sid 10bf
will try more later/tomorrow.
I notice there are a couple of suspect bitwise | but changing to ||
didn't help.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
diff --git a/lib/libdvbv5/dvb-demux.c b/lib/libdvbv5/dvb-demux.c
index 867d7b9dddde..af124ae3a7cc 100644
--- a/lib/libdvbv5/dvb-demux.c
+++ b/lib/libdvbv5/dvb-demux.c
@@ -30,6 +30,7 @@
#include <string.h>
#include <unistd.h>
#include <stdio.h>
+#include <time.h>
#include <errno.h>
#include <sys/ioctl.h>
@@ -40,12 +41,25 @@
#include <libdvbv5/dvb-demux.h>
+#define MAX_TIME 10 /* 1.0 seconds */
+
#define xioctl(fh, request, arg...) ({ \
- int __rc, __retry; \
+ int __rc; \
+ struct timespec __start, __end; \
\
- for (__retry = 0; __retry < 10; __retry++) { \
+ clock_gettime(CLOCK_MONOTONIC, &__start); \
+ do { \
__rc = ioctl(fh, request, ##arg); \
- } while (__rc == -1 && ((errno == EINTR) || (errno == EAGAIN)));\
+ if (__rc != -1) \
+ break; \
+ if (!((errno == EINTR) | (errno == EAGAIN))) \
+ break; \
+ clock_gettime(CLOCK_MONOTONIC, &__end); \
+ if (__end.tv_sec * 10 + __end.tv_nsec / 100000000 > \
+ __start.tv_sec * 10 + __start.tv_nsec / 100000000 + \
+ MAX_TIME) \
+ break; \
+ } while (1); \
\
__rc; \
})
diff --git a/lib/libdvbv5/dvb-fe.c b/lib/libdvbv5/dvb-fe.c
index 48b09cd9ceaa..8607401841f2 100644
--- a/lib/libdvbv5/dvb-fe.c
+++ b/lib/libdvbv5/dvb-fe.c
@@ -26,6 +26,7 @@
#include <inttypes.h>
#include <math.h>
#include <stddef.h>
+#include <time.h>
#include <unistd.h>
#include <config.h>
@@ -43,12 +44,25 @@ static int libdvbv5_initialized = 0;
# define N_(string) string
+#define MAX_TIME 10 /* 1.0 seconds */
+
#define xioctl(fh, request, arg...) ({ \
- int __rc, __retry; \
+ int __rc; \
+ struct timespec __start, __end; \
\
- for (__retry = 0; __retry < 10; __retry++) { \
+ clock_gettime(CLOCK_MONOTONIC, &__start); \
+ do { \
__rc = ioctl(fh, request, ##arg); \
- } while (__rc == -1 && ((errno == EINTR) || (errno == EAGAIN)));\
+ if (__rc != -1) \
+ break; \
+ if (!((errno == EINTR) | (errno == EAGAIN))) \
+ break; \
+ clock_gettime(CLOCK_MONOTONIC, &__end); \
+ if (__end.tv_sec * 10 + __end.tv_nsec / 100000000 > \
+ __start.tv_sec * 10 + __start.tv_nsec / 100000000 + \
+ MAX_TIME) \
+ break; \
+ } while (1); \
\
__rc; \
})
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