On Monday 15 August 2016 09:15 PM, Jonathan Cameron wrote:

On 08/08/16 12:05, Vignesh R wrote:

quoted

It is possible that two or more ADC channels can be simultaneously
requested for raw samples, in which case there can be race in access to
FIFO data resulting in loss of samples.
If am335x_tsc_se_set_once() is called again from tiadc_read_raw(), when
ADC is still acquired to sample one of the channels, the second process
might be put into uninterruptible sleep state. Fix these issues, by
protecting FIFO access and channel configurations with a mutex. Since
tiadc_read_raw() might take anywhere between few microseconds to few
milliseconds to finish execution (depending on averaging and delay
values supplied via DT), its better to use mutex instead of spinlock.

Signed-off-by: Vignesh R <vigneshr@ti.com>

Hi,

Thanks for the patch.

As this is clearly a fix for a long standing issue, I'd like to send
it for stable inclusion.  Would you mind doing a bit of detective work
to added a Fixes tag to say which original patch introduced the issue?

Looks to be due to the commit 7ca6740cd1cd4 ("mfd: input: iio:
ti_amm335x: Rework TSC/ADC synchronization")
Will send v2 with fixes tag. Thanks!

-- 
Regards
Vignesh