Re: [PATCH 2/7] firmware: add offset to request_firmware_into_buf

From: Takashi Iwai
Date: Mon Aug 26 2019 - 11:20:57 EST

On Fri, 23 Aug 2019 21:44:42 +0200,
Scott Branden wrote:
> Hi Takashi,
> Thanks for review. comments below.
> On 2019-08-23 3:05 a.m., Takashi Iwai wrote:
> > On Thu, 22 Aug 2019 21:24:46 +0200,
> > Scott Branden wrote:
> >> Add offset to request_firmware_into_buf to allow for portions
> >> of firmware file to be read into a buffer. Necessary where firmware
> >> needs to be loaded in portions from file in memory constrained systems.
> > AFAIU, this won't work with the fallback user helper, right?
> Seems to work fine in the with fallbacks.

But how? You patch doesn't change anything about the fallback loading
mechanism. Or, if the expected behavior is to load the whole content
and then copy a part, what's the merit of this API?

> > Also it won't work for the compressed firmware files as-is.
> Although unnecessary, seems to work fine in the with
> "both" and "xzonly" options.

This looks also suspicious. Loading a part of the file from the
middle and decompression won't work together, from obvious reasons.

If the test passes, it means that the test itself is more likely
incorrect, I'm afraid.