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From:   Kalle Valo <kvalo@kernel.org>
To:     Abhishek Kumar <kuabhs@chromium.org>
Cc:     Doug Anderson <dianders@chromium.org>,
        Rakesh Pillai <pillair@codeaurora.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        ath10k <ath10k@lists.infradead.org>,
        netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH 1/2] ath10k: search for default BDF name provided in DT
References: <20220107200417.1.Ie4dcc45b0bf365077303c596891d460d716bb4c5@changeid>
        <CAD=FV=W5fHP8K-PcoYWxYHiDWnPUVQQzOzw=REbuJSSqGeVVfg@mail.gmail.com>
        <87sfrqqfzy.fsf@kernel.org>
        <CAD=FV=U0Qw-OnKJg8SWk9=e=B0qgqnaTHpuR0cRA0WCmSHSJYQ@mail.gmail.com>
        <CACTWRwtpYBokTehRE0_zSdSjio6Ga1yqdCfj1TNck7SqOT8o_Q@mail.gmail.com>
Date:   Tue, 12 Apr 2022 13:46:55 +0300
In-Reply-To: <CACTWRwtpYBokTehRE0_zSdSjio6Ga1yqdCfj1TNck7SqOT8o_Q@mail.gmail.com>
        (Abhishek Kumar's message of "Mon, 11 Apr 2022 16:25:10 -0700")
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Abhishek Kumar <kuabhs@chromium.org> writes:

> Hi All,
>
> Apologies for the late reply, too many things at the same time.

Trust me, I know the feeling :)

> Just a quick note, Qcomm provided a new BDF file with support for
> 'bus=snoc,qmi-board-id=ff' as well, so even without this patch, the
> non-programmed devices(with board-id=0xff) would work. However, for
> optimization of the BDF search strategy, the above mentioned strategy
> would still not work: - The stripping of full Board name would not
> work if board-id itself is not programmed i.e. =0xff e.g. for
> 'bus=snoc,qmi-board-id=ff,qmi-chip-id=320,variant=GO_LAZOR' => no
> match 'bus=snoc,qmi-board-id=ff,qmi-chip-id=320' => no match
> 'bus=snoc,qmi-board-id=ff' => no match 'bus=snoc' => no match because
> all the BDFs contains board-id=67

Sorry, not fully following your here. Are you saying that the problem is
that WCN3990/hw1.0/board-2.bin is missing board file for 'bus=snoc'?
That's easy to add, each board file within board-2.bin has multiple
names so we can easily select one board file for which we add
'bus=snoc'.

> So with this DT patch specifically for case 'bus=snoc,qmi-board-id=ff'
> => no match, we fallback to default case ( the one provided in DT)
> i.e. 'bus=snoc,qmi-board-id=67' => match . I do not see how exactly
> the driver can know that it should check for a board-id of 67.

Sorry, not following you here either. Why would the driver need to use
board-id 67?

> However, to still remove dependency on the DT, we can make the
> board-id as no-op if it is not programmed i.e. if the board-id=ff then
> we would pick any BDF that match 'bus=snoc,qmi-board-id=<XX>' where XX
> can be any arbitrary number. Thoughts ?

To me using just 'bus=snoc' is more logical than picking up an arbitrary
number. But I might be missing something here.

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