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Date: Tue, 2 Apr 2024 10:13:36 +0800
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Subject: Re: [PATCH v2] power: supply: bq27xxx: Divide the reg cache to each
 register
To: Sebastian Reichel <sebastian.reichel@collabora.com>,
 Hermes Zhang <Hermes.Zhang@axis.com>
Cc: kernel@axis.com, =?UTF-8?Q?Pali_Roh=c3=a1r?= <pali@kernel.org>,
 linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
 Andrew Davis <afd@ti.com>
References: <20240306100904.1914263-1-Hermes.Zhang@axis.com>
 <c4u27576oazfrlcp5avy3ect3i4jlsmdvi7nlun5qvez3ipti2@ue5jxbydmevs>
From: Hermes Zhang <chenhuiz@axis.com>
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On 2024/4/1 21:15, Sebastian Reichel wrote:
> [+cc Andrew Davis]
>
> Hello Hermes,
>
> Sorry for the delay. This arrived too close to the 6.9 merge window.
> I had a look now and while the patch looks fine to me on a conceptual
> level, it did not apply. It looks like you used a pre-2024 kernel tree
> to generate the patch against. Please always use something recent base
> tree (and ideally use git's --base option to document the used
> parent commit).

Ack.

> Other than that I just applied a series from Andrew, which cleans up
> the register caching in bq27xxx and removed most registers from the
> cache. That's something I did not consider earlier, since I thought
> the cache was introduced to fix a different issue. But that was
> apparently sbs-battery and not bq27xxx.
>
> Anyways, there is only two registers left in the cache now. I'm fine
> with having a per-register cache for them, if that is still needed
> to further reduce I2C traffic on your device.
>
> And... re-reading your problem description, I wonder if we need to
> reintroduce the caching for all registers (on a per register basis)
> to avoid userspace being able to do a denial of service by quickly
> polling the battery information.
>
> Any thoughts?

Great. Now I think I can drop my patch since the current code is almost 
same as we expected and still keep simple. Thanks for the latest info.


Best Regards,

Hermes