linux-kernel - Re: [PATCH] ath10k: search all IEs for variant before falling back

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Message-ID: <87y3jcp0kz.fsf@kamboji.qca.qualcomm.com>
Date:   Thu, 01 Mar 2018 12:11:24 +0200
From:   Kalle Valo <kvalo@...eaurora.org>
To:     Thomas Hebb <tommyhebb@...il.com>
Cc:     ath10k@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ath10k: search all IEs for variant before falling back

Thomas Hebb <tommyhebb@...il.com> writes:

> commit f2593cb1b291 ("ath10k: Search SMBIOS for OEM board file
> extension") added a feature to ath10k that allows Board Data File
> (BDF) conflicts between multiple devices that use the same device IDs
> but have different calibration requirements to be resolved by allowing
> a "variant" string to be stored in SMBIOS [and later device tree, added
> by commit d06f26c5c8a4 ("ath10k: search DT for qcom,ath10k-calibration-
> variant")] that gets appended to the ID stored in board-2.bin.
>
> This original patch had a regression, however. Namely that devices with
> a variant present in SMBIOS that didn't need custom BDFs could no longer
> find the default BDF, which has no variant appended. The patch was
> reverted and re-applied with a fix for this issue in commit 1657b8f84ed9
> ("search SMBIOS for OEM board file extension").
>
> But the fix to fall back to a default BDF introduced another issue: the
> driver currently parses IEs in board-2.bin one by one, and for each one
> it first checks to see if it matches the ID with the variant appended.
> If it doesn't, it checks to see if it matches the "fallback" ID with no
> variant. If a matching BDF is found at any point during this search, the
> search is terminated and that BDF is used. The issue is that it's very
> possible (and is currently the case for board-2.bin files present in the
> ath10k-firmware repository) for the default BDF to occur in an earlier
> IE than the variant-specific BDF. In this case, the current code will
> happily choose the default BDF even though a better-matching BDF is
> present later in the file.
>
> This patch fixes the issue by first searching the entire file for the ID
> with variant, and searching for the fallback ID only if that search
> fails. It also includes some code cleanup in the area, as
> ath10k_core_fetch_board_data_api_n() no longer does its own string
> mangling to remove the variant from an ID, instead leaving that job to a
> new flag passed to ath10k_core_create_board_name().
>
> I've tested this patch on a QCA4019 and verified that the driver behaves
> correctly for 1) both fallback and variant BDFs present, 2) only fallback
> BDF present, and 3) no matching BDFs present.
>
> Fixes: 1657b8f84ed9 ("ath10k: search SMBIOS for OEM board file extension")
> Signed-off-by: Thomas Hebb <tommyhebb@...il.com>

BTW, you forgot to CC linux-wireless so I don't see this in patchwork.

https://wireless.wiki.kernel.org/en/users/drivers/ath10k/submittingpatches

-- 
Kalle Valo