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From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To:     Wen Gong <wgong@qti.qualcomm.com>, Wen Gong <wgong@codeaurora.org>,
        "ath10k\@lists.infradead.org" <ath10k@lists.infradead.org>
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Subject: RE: [PATCH 4/7] ath10k: disable TX complete indication of htt for sdio
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Date:   Thu, 22 Aug 2019 14:12:01 +0200
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Wen Gong <wgong@qti.qualcomm.com> writes:

>> -----Original Message-----
>> From: Toke Høiland-Jørgensen <toke@redhat.com>
>> Sent: Wednesday, August 21, 2019 6:10 PM
>> To: Wen Gong <wgong@qti.qualcomm.com>; Wen Gong
>> <wgong@codeaurora.org>; ath10k@lists.infradead.org
>> Cc: linux-wireless@vger.kernel.org
>> Subject: [EXT] RE: [PATCH 4/7] ath10k: disable TX complete indication of htt
>> for sdio
>> 
>> Wen Gong <wgong@qti.qualcomm.com> writes:
>> 
>> >> -----Original Message-----
>> >> From: ath10k <ath10k-bounces@lists.infradead.org> On Behalf Of Toke
>> >> Høiland-Jørgensen
>> >> Sent: Tuesday, August 20, 2019 8:24 PM
>> >> To: Wen Gong <wgong@codeaurora.org>; ath10k@lists.infradead.org
>> >> Cc: linux-wireless@vger.kernel.org
>> >> Subject: [EXT] Re: [PATCH 4/7] ath10k: disable TX complete indication of
>> htt
>> > When this patch applied, firmware will not indicate tx complete for tx
>> > Data, it only indicate HTT_T2H_MSG_TYPE_TX_CREDIT_UPDATE_IND,
>> > This htt msg will tell how many data tx complete without status(status
>> maybe success/fail).
>> 
>> Ah, so this is basically a counter of how much data is currently queued
>> in the firmware?
> Yes.
>> 
>> >> And could you explain what the credits thing is for, please? :)
>> > For high latency bus chip, all the tx data's content(include ip/udp/tcp
>> header
>> > and payload) will be transfer to firmware's memory via bus.
>> > And firmware has limited memory for tx data, the tx data's content must
>> > Saved in firmware memory before it tx complete, if ath10k transfer tx
>> > data more than the limit, firmware will occur error. The credit is used
>> > to avoid ath10k exceed the limit.
>> 
>> What's a typical limit in the firmware?
> It is 96 data packet in my test. It can changed in firmware code.

Right, I see. Is this counter available in all ath10k firmware, or is it
SDIO only?

I'm asking because this could also be a way of implementing something
like Byte Queue Limits (though I'm not sure how effective it would be).

-Toke