Message-ID: <5e46e5dc-cb38-4851-875f-732c99c5f34f@kernel.org>
Date: Tue, 11 Jun 2024 09:36:08 +0200
From: Jiri Slaby <jirislaby@...nel.org>
To: Ferry Toth <fntoth@...il.com>, neil.armstrong@...aro.org,
 gregkh@...uxfoundation.org
Cc: linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
 Al Cooper <alcooperx@...il.com>, Alexander Shiyan <shc_work@...l.ru>,
 Alexandre Belloni <alexandre.belloni@...tlin.com>,
 Alexandre Torgue <alexandre.torgue@...s.st.com>,
 Alim Akhtar <alim.akhtar@...sung.com>,
 Andrew Morton <akpm@...ux-foundation.org>,
 "Aneesh Kumar K.V" <aneesh.kumar@...nel.org>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 Baolin Wang <baolin.wang@...ux.alibaba.com>, Baruch Siach
 <baruch@...s.co.il>, Bjorn Andersson <andersson@...nel.org>,
 Claudiu Beznea <claudiu.beznea@...on.dev>,
 "David S. Miller" <davem@...emloft.net>, Fabio Estevam <festevam@...il.com>,
 Hammer Hsieh <hammerh0314@...il.com>,
 Christian König <christian.koenig@....com>,
 Christophe Leroy <christophe.leroy@...roup.eu>,
 Chunyan Zhang <zhang.lyra@...il.com>, Jerome Brunet <jbrunet@...libre.com>,
 Jonathan Hunter <jonathanh@...dia.com>, Kevin Hilman <khilman@...libre.com>,
 Konrad Dybcio <konrad.dybcio@...aro.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
 Kumaravel Thiagarajan <kumaravel.thiagarajan@...rochip.com>,
 Laxman Dewangan <ldewangan@...dia.com>,
 linux-arm-kernel@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
 "Maciej W. Rozycki" <macro@...am.me.uk>,
 Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
 Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
 Matthias Brugger <matthias.bgg@...il.com>,
 Maxime Coquelin <mcoquelin.stm32@...il.com>,
 Michael Ellerman <mpe@...erman.id.au>, Michal Simek <michal.simek@....com>,
 "Naveen N. Rao" <naveen.n.rao@...ux.ibm.com>,
 Nicolas Ferre <nicolas.ferre@...rochip.com>,
 Nicholas Piggin <npiggin@...il.com>, Orson Zhai <orsonzhai@...il.com>,
 Pali Rohár <pali@...nel.org>,
 Patrice Chotard <patrice.chotard@...s.st.com>,
 Peter Korsgaard <jacmet@...site.dk>,
 Richard Genoud <richard.genoud@...il.com>,
 Russell King <linux@...linux.org.uk>, Sascha Hauer <s.hauer@...gutronix.de>,
 Shawn Guo <shawnguo@...nel.org>, Stefani Seibold <stefani@...bold.net>,
 Sumit Semwal <sumit.semwal@...aro.org>,
 Taichi Sugaya <sugaya.taichi@...ionext.com>,
 Takao Orito <orito.takao@...ionext.com>,
 Tharun Kumar P <tharunkumar.pasumarthi@...rochip.com>,
 Thierry Reding <thierry.reding@...il.com>, Timur Tabi <timur@...nel.org>,
 Vineet Gupta <vgupta@...nel.org>, Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH 00/15] tty: serial: switch from circ_buf to kfifo

On 10. 06. 24, 22:16, Ferry Toth wrote:
>> One question though: in 8250_dma.c serial8250_tx_dma() you mention "/* 
>> kfifo can do more than one sg, we don't (quite yet) */".
>>
>> I see the opportunity to use 2 sg entries to get all the data out in 
>> one dma transfer, but there doesn't seem to be much documentation or 
>> examples on how to do that. It seems just increasing nents to 2 would 
>> do the trick?
> 
> Nevertheless I got this to work. Very nice. Thanks for this series.
> I am seeing only 2 interrupts (x2 as each interrupt happens twice), one 
> for dma complete. The 2nd, not sure but likely, uart tx done.
> In any case the whole buffer is transferred without interchar gaps.
> 
>> So, what was the reason to "don't (quite yet)"?
> 
> Before considering to send out a patch for this, are there any caveats 
> that I'm overlooking?

Not any I am aware of. It just needed testers.

Please send a patch.

thanks,
-- 
js
suse labs

Powered by blists - more mailing lists