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.
--
Thanks,
Sasha
