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From: Mark Brown <broonie@kernel.org>
To: Mark Tomlinson <Mark.Tomlinson@alliedtelesis.co.nz>
Cc: "linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
	"kdasu.kdev@gmail.com" <kdasu.kdev@gmail.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/5] spi: bcm-qspi: Make multiple data blocks interrupt-driven
Date: Tue, 16 Jun 2020 09:26:48 +0100	[thread overview]
Message-ID: <20200616082648.GE4447@sirena.org.uk> (raw)
In-Reply-To: <40bae0160c6e24c3d90d4935eb31cf3de64abc9e.camel@alliedtelesis.co.nz>

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On Tue, Jun 16, 2020 at 03:07:17AM +0000, Mark Tomlinson wrote:
> On Mon, 2020-06-15 at 15:32 +0100, Mark Brown wrote:

> > Again was this done for a reason and if so do we understand why doing
> > this from interrupt context is safe - how long can the interrupts be
> > when stuffing the FIFO from interrupt context?

> As I'm porting a Broadcom patch, I'm hoping someone else can add
> something to this. From the history it appears there was a hard limit

If you didn't write this code then it should have at least one signoff
from the original source, I can't do anything with this without signoffs
- please see Documentation/process/submitting-patches.rst for what this
is and why it's important.

> (no small chunks), and this was changed to doing it in chunks with
> patch 345309fa7c0c92, apparently to improve performance. I believe this
> change further improves performance, but as the patch arrived without
> any documentation, I'm not certain.

Have you tested the impact on performance?

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  reply	other threads:[~2020-06-16  8:26 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-15  4:05 [PATCH 0/5] Improvements to spi-bcm-qspi Mark Tomlinson
2020-06-15  4:05 ` [PATCH 1/5] spi: bcm-qspi: Add support for setting BSPI clock Mark Tomlinson
2020-06-15  4:05 ` [PATCH 2/5] spi: bcm-qspi: Improve debug reading SPI data Mark Tomlinson
2020-06-15  4:05 ` [PATCH 3/5] spi: bcm-qspi: Do not split transfers into small chunks Mark Tomlinson
2020-06-15 13:31   ` Mark Brown
2020-06-15  4:05 ` [PATCH 4/5] spi: bcm-qspi: Make multiple data blocks interrupt-driven Mark Tomlinson
2020-06-15 14:32   ` Mark Brown
2020-06-16  3:07     ` Mark Tomlinson
2020-06-16  8:26       ` Mark Brown [this message]
2020-06-15  4:05 ` [PATCH 5/5] spi: bcm-qspi: Improve interrupt handling Mark Tomlinson
2020-06-15 19:05 ` [PATCH 0/5] Improvements to spi-bcm-qspi Kamal Dasu

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