Re: [PATCH] i2c-designware: increase timeout of semaphore transfer

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 16-03-17 17:35, Andy Shevchenko wrote:
> On Thu, 2017-03-16 at 17:24 +0100, Oliver Neukum wrote:
>> Our testing shows the semaphore failing to be transferred on
>> CherryTrail
>> in about 0.5% of all cases. The existing timeout needs to be
>> lengthened
>> to accomodate the worst cases.
>
> I think it's just a semi-hiding of real issue.

I would not know what real issue, I've seen the timeout being
hit sometimes too, it seems that sometimes the punit just is
busy with other stuff for a while before acking the semaphore
request, so I think this patch is fine:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Oliver, can you rebase this on top of:


https://cgit.freedesktop.org/drm-intel/commit/?h=topic/designware-baytrail

Which is in -next now, please ? I'm sorta surprised you didn't
use this is a base since your commit msg mentions cherrytrail
and with that series the semaphore code is broken on
cherrytrail.

Regards,

Hans



>
> Hans?
>
>>
>> Signed-off-by: Oliver Neukum <oneukum@suse.com>
>> ---
>>  drivers/i2c/busses/i2c-designware-baytrail.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c
>> b/drivers/i2c/busses/i2c-designware-baytrail.c
>> index 1590ad0..2d238e3 100644
>> --- a/drivers/i2c/busses/i2c-designware-baytrail.c
>> +++ b/drivers/i2c/busses/i2c-designware-baytrail.c
>> @@ -21,7 +21,7 @@
>>
>>  #include "i2c-designware-core.h"
>>
>> -#define SEMAPHORE_TIMEOUT	100
>> +#define SEMAPHORE_TIMEOUT	500
>>  #define PUNIT_SEMAPHORE		0x7
>>  #define PUNIT_SEMAPHORE_BIT	BIT(0)
>>  #define PUNIT_SEMAPHORE_ACQUIRE	BIT(1)
>