This is a note to let you know that I've just added the patch titled arm64: dts: rockchip: fix rk3399-puma eMMC HS400 signal integrity to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm64-dts-rockchip-fix-rk3399-puma-emmc-hs400-signal.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 34157ca6667de1e8024aff2fd41c67829a49e43a Author: Jakob Unterwurzacher <jakob.unterwurzacher@xxxxxxxxxxxxxxxxxxxxx> Date: Wed Jan 19 14:49:48 2022 +0100 arm64: dts: rockchip: fix rk3399-puma eMMC HS400 signal integrity [ Upstream commit 62966cbdda8a92f82d966a45aa671e788b2006f7 ] There are signal integrity issues running the eMMC at 200MHz on Puma RK3399-Q7. Similar to the work-around found for RK3399 Gru boards, lowering the frequency to 100MHz made the eMMC much more stable, so let's lower the frequency to 100MHz. It might be possible to run at 150MHz as on RK3399 Gru boards but only 100MHz was extensively tested. Cc: Quentin Schulz <foss+kernel@xxxxxxxxx> Signed-off-by: Jakob Unterwurzacher <jakob.unterwurzacher@xxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220119134948.1444965-1-quentin.schulz@xxxxxxxxxxxxxxxxxxxxx Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi index 0d5679380b2a..70fe6013d17c 100644 --- a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi +++ b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi @@ -484,6 +484,12 @@ }; &sdhci { + /* + * Signal integrity isn't great at 200MHz but 100MHz has proven stable + * enough. + */ + max-frequency = <100000000>; + bus-width = <8>; mmc-hs400-1_8v; mmc-hs400-enhanced-strobe;