* [PATCH RFC] media: radio: handle timeouts
@ 2015-02-05 8:56 Nicholas Mc Guire
2015-02-16 11:19 ` Hans Verkuil
0 siblings, 1 reply; 2+ messages in thread
From: Nicholas Mc Guire @ 2015-02-05 8:56 UTC (permalink / raw)
To: Mauro Carvalho Chehab
Cc: Hans Verkuil, Wolfram Sang, linux-media, linux-kernel, Nicholas Mc Guire
Add handling for timeout case.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
---
Some error state/error information seems be get lost int the current code.
(line-numbers are from 3.19.0-rc7.
Assume that on line 827 core->write succeeds but the following
wait_for_completion_timeout times out and the radio->irq_received condition
is not satisfied resulting in goto out;
827 r = core->write(core, WL1273_TUNER_MODE_SET, TUNER_MODE_AUTO_SEEK);
828 if (r)
829 goto out;
830
831 wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000));
832 if (!(radio->irq_received & WL1273_BL_EVENT))
833 goto out;
A similar situation is at line 955 - 859 where a tiemout could occure
and the reported value would be the success value from core->write.
852 reinit_completion(&radio->busy);
853 dev_dbg(radio->dev, "%s: BUSY\n", __func__);
854
855 r = core->write(core, WL1273_TUNER_MODE_SET, TUNER_MODE_AUTO_SEEK);
856 if (r)
857 goto out;
858
859 wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000)
the problem is that the value of r now is the "success" value from core->write
and any timeout and/or failure to detect the expected interrupt is not
reported in
860 out:
861 dev_dbg(radio->dev, "%s: Err: %d\n", __func__, r);
862 return r;
Should the wait_for_completion_timeout not report the timeout event by setting
r to -ETIMEOUT ? respectively use if (!(radio->irq_received & WL1273_BL_EVENT))
to check and set -ETIMEOUT there ?
Comparing this with wl1273_fm_set_tx_freq - the below patch might be suitable
way to handle timeout - but this needs a review by someone who knows the
details of the driver - so this is really just a guess.
Patch was only compile tested with x86_64_defconfig + CONFIG_MEDIA_SUPPORT=m
CONFIG_MEDIA_CAMERA_SUPPORT=y, CONFIG_V4L_PLATFORM_DRIVERS=y,
CONFIG_MEDIA_RADIO_SUPPORT=y, RADIO_ADAPTER=y, CONFIG_RADIO_WL1273=m
Patch is against 3.19.0-rc7 (localversion-next is -next-20150204)
drivers/media/radio/radio-wl1273.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/media/radio/radio-wl1273.c b/drivers/media/radio/radio-wl1273.c
index 571c7f6..6830523 100644
--- a/drivers/media/radio/radio-wl1273.c
+++ b/drivers/media/radio/radio-wl1273.c
@@ -828,9 +828,12 @@ static int wl1273_fm_set_seek(struct wl1273_device *radio,
if (r)
goto out;
+ /* wait for the FR IRQ */
wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000));
- if (!(radio->irq_received & WL1273_BL_EVENT))
+ if (!(radio->irq_received & WL1273_BL_EVENT)) {
+ r = -ETIMEDOUT;
goto out;
+ }
radio->irq_received &= ~WL1273_BL_EVENT;
@@ -856,7 +859,9 @@ static int wl1273_fm_set_seek(struct wl1273_device *radio,
if (r)
goto out;
- wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000));
+ /* wait for the FR IRQ */
+ if (!wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000)))
+ r = -ETIMEDOUT;
out:
dev_dbg(radio->dev, "%s: Err: %d\n", __func__, r);
return r;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH RFC] media: radio: handle timeouts
2015-02-05 8:56 [PATCH RFC] media: radio: handle timeouts Nicholas Mc Guire
@ 2015-02-16 11:19 ` Hans Verkuil
0 siblings, 0 replies; 2+ messages in thread
From: Hans Verkuil @ 2015-02-16 11:19 UTC (permalink / raw)
To: Nicholas Mc Guire, Mauro Carvalho Chehab
Cc: Hans Verkuil, Wolfram Sang, linux-media, linux-kernel
Hi Nicholas,
On 02/05/2015 09:56 AM, Nicholas Mc Guire wrote:
> Add handling for timeout case.
>
> Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
> ---
> Some error state/error information seems be get lost int the current code.
> (line-numbers are from 3.19.0-rc7.
>
> Assume that on line 827 core->write succeeds but the following
> wait_for_completion_timeout times out and the radio->irq_received condition
> is not satisfied resulting in goto out;
>
> 827 r = core->write(core, WL1273_TUNER_MODE_SET, TUNER_MODE_AUTO_SEEK);
> 828 if (r)
> 829 goto out;
> 830
> 831 wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000));
> 832 if (!(radio->irq_received & WL1273_BL_EVENT))
> 833 goto out;
>
>
> A similar situation is at line 955 - 859 where a tiemout could occure
> and the reported value would be the success value from core->write.
>
> 852 reinit_completion(&radio->busy);
> 853 dev_dbg(radio->dev, "%s: BUSY\n", __func__);
> 854
> 855 r = core->write(core, WL1273_TUNER_MODE_SET, TUNER_MODE_AUTO_SEEK);
> 856 if (r)
> 857 goto out;
> 858
> 859 wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000)
>
> the problem is that the value of r now is the "success" value from core->write
> and any timeout and/or failure to detect the expected interrupt is not
> reported in
>
> 860 out:
> 861 dev_dbg(radio->dev, "%s: Err: %d\n", __func__, r);
> 862 return r;
>
> Should the wait_for_completion_timeout not report the timeout event by setting
> r to -ETIMEOUT ? respectively use if (!(radio->irq_received & WL1273_BL_EVENT))
> to check and set -ETIMEOUT there ?
>
> Comparing this with wl1273_fm_set_tx_freq - the below patch might be suitable
> way to handle timeout - but this needs a review by someone who knows the
> details of the driver - so this is really just a guess.
While I am certainly not an expert, I agree that the current situation is bad.
I'm taking your patch as-is, since returning a proper error here seems to make
much more sense.
Regards,
Hans
>
> Patch was only compile tested with x86_64_defconfig + CONFIG_MEDIA_SUPPORT=m
> CONFIG_MEDIA_CAMERA_SUPPORT=y, CONFIG_V4L_PLATFORM_DRIVERS=y,
> CONFIG_MEDIA_RADIO_SUPPORT=y, RADIO_ADAPTER=y, CONFIG_RADIO_WL1273=m
>
> Patch is against 3.19.0-rc7 (localversion-next is -next-20150204)
>
> drivers/media/radio/radio-wl1273.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/radio/radio-wl1273.c b/drivers/media/radio/radio-wl1273.c
> index 571c7f6..6830523 100644
> --- a/drivers/media/radio/radio-wl1273.c
> +++ b/drivers/media/radio/radio-wl1273.c
> @@ -828,9 +828,12 @@ static int wl1273_fm_set_seek(struct wl1273_device *radio,
> if (r)
> goto out;
>
> + /* wait for the FR IRQ */
> wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000));
> - if (!(radio->irq_received & WL1273_BL_EVENT))
> + if (!(radio->irq_received & WL1273_BL_EVENT)) {
> + r = -ETIMEDOUT;
> goto out;
> + }
>
> radio->irq_received &= ~WL1273_BL_EVENT;
>
> @@ -856,7 +859,9 @@ static int wl1273_fm_set_seek(struct wl1273_device *radio,
> if (r)
> goto out;
>
> - wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000));
> + /* wait for the FR IRQ */
> + if (!wait_for_completion_timeout(&radio->busy, msecs_to_jiffies(1000)))
> + r = -ETIMEDOUT;
> out:
> dev_dbg(radio->dev, "%s: Err: %d\n", __func__, r);
> return r;
>
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