Re: [PATCH v5] RFT: mmc: sdhci: Implement an SDHCI-specific bounce buffer

[Adrian Hunter <adrian.hunter@intel.com>]

On 15/01/18 12:54, Adrian Hunter wrote:
> On 15/01/18 11:53, Linus Walleij wrote:
>> On Mon, Jan 15, 2018 at 7:07 AM, Benjamin Beckmeyer
>> <beckmeyer.b@rittal.de> wrote:
>>
>>> Good morning,
>>>
>>>> - Requesting a test of this on i.MX. (Sorry Benjamin.)
>>>
>>> No worries. I did another test with your v5 patch, but it doesn't work.
>>
>> Wow that is weird.
>>
>> So v3 works.
>>
>> And it's not the code that bails out if we have nr_segs == 1
>> because that code path is not taken.
>>
>> It is the 64K instead of 512K buffer that makes this happen,
>> then.
> 
> That might be because you are not updating max_req_size.
> 
>> I guess I just respin v3 with the change that we fall back to
>> 1 segment if we can's allocate coherent memory for the
>> bounce buffer.
> 
> I would like to support pre_req() and post_req().  I have some code for that
> if you are interested.
> 

Then again it depends on the amount of memory allocated.  In some cases, one
big buffer will probably be better than 2 half the size.