On Mon, 2019-11-11 at 08:51 -0500, Sasha Levin wrote:
> On Mon, Nov 11, 2019 at 07:23:01AM +0100, gregkh@xxxxxxxxxxxxxxxxxxx
> wrote:
> >
> > The patch below does not apply to the 5.3-stable tree.
> > If someone wants it applied there, or to any other stable or
> > longterm
> > tree, then please email the backport, including the original git
> > commit
> > id to <stable@xxxxxxxxxxxxxxx>.
> >
> > thanks,
> >
> > greg k-h
> >
> > ------------------ original commit in Linus's tree ----------------
> > --
> >
> > From b234fe9558615098d8d62516e7041ad7f99ebcea Mon Sep 17 00:00:00
> > 2001
> > From: Leonard Crestez <leonard.crestez@xxxxxxx>
> > Date: Tue, 22 Oct 2019 22:21:28 +0300
> > Subject: [PATCH] clk: imx8m: Use SYS_PLL1_800M as intermediate
> > parent of
> > CLK_ARM
> >
> > During cpu frequency switching the main "CLK_ARM" is reparented to
> > an
> > intermediate "step" clock. On imx8mm and imx8mn the 24M oscillator
> > is
> > used for this purpose but it is extremely slow, increasing wakeup
> > latencies to the point that i2c transactions can timeout and system
> > becomes unresponsive.
> >
> > Fix by switching the "step" clk to SYS_PLL1_800M, matching the
> > behavior
> > of imx8m cpufreq drivers in imx vendor tree.
> >
> > This bug was not immediately apparent because upstream arm64
> > defconfig
> > uses the "performance" governor by default so no cpufreq
> > transitions
> > happen.
> >
> > Fixes: ba5625c3e272 ("clk: imx: Add clock driver support for
> > imx8mm")
> > Fixes: 96d6392b54db ("clk: imx: Add support for i.MX8MN clock
> > driver")
>
> 96d6392b54db doesn't exist on 5.3, so I've modified the patch to only
> fix the ba5625c3e272 related code and queued it for 5.3. Neither
> commit
> exists on 4.19 and older.
Hello,
The patch fixes the same bug for two very similar SOCs which were
upstreamed at different times. It is safe to split the patch.
--
Regards,
Leonard
