linux-kernel - Re: [PATCH] spi: spidev: Fix for reverting spi max speed value only on failure

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Message-ID: <20190603155714.GY2456@sirena.org.uk>
Date:   Mon, 3 Jun 2019 16:57:14 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Vivek Pernamitta <pervivek@...il.com>
Cc:     linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] spi: spidev: Fix for reverting spi max speed value only
 on failure

On Sun, Jun 02, 2019 at 07:49:59PM +0530, Vivek Pernamitta wrote:
> When user space application request for change in spi clock
> using ioctl, current value is taken back-up and new value is
> assigned to spi->max_speed_hz, then spi_setup() function is
> called with new value. If spi_setup() function fails, it needs
> reverting to old spi_max_speed value only in failure condition.

The current behaviour is intentional, we're not modifying max_speed_hz
so we can continue to enforce the kernel limit no matter what userspace
asked for - actually looking at the code we should probably have an
explicit error check in there to reject attempts to raise it here, not
sure why we're not doing that already.

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