Re: [PATCH v3 09/15] ASoC: tegra: Add fallback for audio mclk

From: Dmitry Osipenko
Date: Mon Dec 09 2019 - 15:32:06 EST

09.12.2019 19:40, Mark Brown ÐÐÑÐÑ:
> On Thu, Dec 05, 2019 at 06:48:49PM -0800, Sowjanya Komatineni wrote:
>> mclk is from clk_out_1 which is part of Tegra PMC block and pmc clocks
>> are moved to Tegra PMC driver with pmc as clock provider and using pmc
>> clock ids.
>> New device tree uses clk_out_1 from pmc clock provider.
>> So, this patch adds fallback to extern1 in case of retrieving mclk fails
>> to be backward compatible of new device tree with older kernels.
>> Cc: stable@xxxxxxxxxxxxxxx
> Why would this need to be a stable fix? Presumably people with stable
> kernels are using the old device tree anyway?

Presumably, yes.

At least Rob Herring is asking to maintain backwards compatibility
because some ditros are using newer device-trees with stable kernels.
I'm personally also tending to use the newer DTB with older kernel
version whenever there is a need to check something using stable kernel.
Perhaps losing sound is not very important, but will be nicer if that
doesn't happen.