christophe.blaess@gmail.com, fred@haapie.com
Bcc: Subject: Re: [PATCH 1/2] spi: spidev: introduce
 SPI_IOC_WR_DEFAULT_MAX_SPEED_HZ command
Reply-To: 
In-Reply-To: [ref]

On Sun, May 14, 2017 at 06:27:16PM +0900, Mark Brown wrote:

On Tue, May 09, 2017 at 02:24:00PM +0200, Seraphime Kirkovski wrote:

quoted

I think, this change is necessary, on the one hand, because there are still
a lot of longterm[2] supported kernels out there, whose users may be relying on
SPI_IOC_WR_MAX_SPEED being system-wide and, on the other hand, this
same command has been exhibiting a different behaviour for 3 years now,
so its users may break, if 9169051617df7 is reverted in one way or
another.

Do we have any evidence that such users exist?  

I can't guarantee for other such users, but this change did disturb our 
workflow. We were using this feature to prototype and test 
hardware/firmware at different speeds.

I was thinking this morning that maybe a sysfs interface will be better 
for setting global settings. Do you prefer ?