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Message-ID: <1181bcdd-1ff4-414b-bc0a-40e513fede08@acm.org>
Date: Thu, 7 Mar 2024 09:32:31 -0800
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Subject: Re: WinLink E850-96: WARNING: at block/blk-settings.c:204
 blk_validate_limits
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To: Christoph Hellwig <hch@lst.de>, Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: linux-block <linux-block@vger.kernel.org>, lkft-triage@lists.linaro.org,
 open list <linux-kernel@vger.kernel.org>, Jens Axboe <axboe@kernel.dk>,
 Christian Brauner <brauner@kernel.org>, Ulf Hansson
 <ulf.hansson@linaro.org>, Arnd Bergmann <arnd@arndb.de>,
 Dan Carpenter <dan.carpenter@linaro.org>,
 Anders Roxell <anders.roxell@linaro.org>
References: <CA+G9fYtddf2Fd3be+YShHP6CmSDNcn0ptW8qg+stUKW+Cn0rjQ@mail.gmail.com>
 <20240229142144.GA8348@lst.de>
From: Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <20240229142144.GA8348@lst.de>
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On 2/29/24 06:21, Christoph Hellwig wrote:
> On Thu, Feb 29, 2024 at 07:44:01PM +0530, Naresh Kamboju wrote:
>> The arm64 WinLink E850-96 Board boot failed with 16K and 64K page size builds
>> Please find the below warning log on Linux next-20240229.
>> First noticed on the next-20240220 tag.
>>
>> This issue arises only when one of these Kconfig options is enabled.
>>    CONFIG_ARM64_16K_PAGES=y
>>    CONFIG_ARM64_64K_PAGES=y
> 
> That means this device doesn't set a max_segment_size, or one smaller
> than the page size.  This configurtio has never been supported by
> Linux (Bart has some patches to try to make it work), but with the
> new block limits API we now actively catch this and warn.

Hi Christoph,

Please let me know if you would like me to repost the patch series that
adds support to the block layer for DMA segments that are smaller than
the page size. Despite my requests to not support such hardware in the
Android kernel, that patch series ended up as an out-of-tree series
in the Android kernel and will continue to be maintained by the Android
core team for considerable time.

Thanks,

Bart.