[PATCH 0/4] add minimal bcm2835-sdram driver

Martin Sperl kernel at martin.sperl.org
Thu May 12 09:03:00 PDT 2016


> On 12.05.2016, at 17:55, Stefan Wahren <stefan.wahren at i2se.com> wrote:
> 
> Hi,
> 
>> Martin Sperl <kernel at martin.sperl.org> hat am 12. Mai 2016 um 17:28
>> geschrieben:
>> 
>> 
>> 
>>> On 12.05.2016, at 16:50, Stefan Wahren <stefan.wahren at i2se.com> wrote:
>>> 
>>> Hi Martin,
>>> 
>>>> kernel at martin.sperl.org hat am 12. Mai 2016 um 14:38 geschrieben:
>>>> 
>>>> 
>>>> From: Martin Sperl <kernel at martin.sperl.org>
>>>> 
>>>> As the sdram clock is a critical clock to the system
>>>> the minimal bcm2835-sdram driver claims (and enables)
>>>> this clock and also exposes the corresponding sdram
>>>> registers via debugfs.
>>> 
>>> sounds like this driver should fix an clock handling issue. Unfortunately
>>> this
>>> isn't a solution in case the driver is disabled.
>> Unfortunately there is no way around this - the driver has
>> to be enabled so that the sdram clock or the parent pll,
>> which typically is plld_core, never gets disabled.
>> 
>> The only other option would be marking the clock as critical
>> for those legacy drivers.
> 
> i would prefer this option. Since this would be more a fix we could get this
> faster in, it's more clear why we are doing that and less to review.
> 
> Did i miss a drawback?

We had long discussions already on that - and HAND_OFF did not make
it into the kernel either.

I had hoped that this was simple enough.

Martin






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