[linux-sunxi] [PATCH] Disable HS-DDR mode for Olimex A64-OLinuXino variants with eMMC

Maxime Ripard maxime at cerno.tech
Thu Oct 22 05:13:37 EDT 2020


Hi,

On Thu, Oct 22, 2020 at 09:52:29AM +0200, Clément Péron wrote:
> Hi Philipp,
> 
> On Thu, 22 Oct 2020 at 00:10, Philip Rinn <rinni at inventati.org> wrote:
> >
> > Hi,
> >
> > the Olimex A64-OLinuXino board comes in various variants, three with eMMC.
> > While MMC HS-DDR mode works fine on one of them (A64-OLinuXino-1Ge4GW) it
> > doesn't work on the A64-OLinuXino-2Ge8G-IND variant (I don't have the
> > third variant so I can't check if it works there).
> 
> We got similar situations for Allwinner H6 (Beelink GS1 and Tanix TX6).
> 
> There is definitely an issue in the MMC sunxi driver with HS-DDR mode
> and it's not limited to "olimex,a64-olinuxino-emmc".
> 
> Have a look at this this message posted by Jernej:
> https://www.spinics.net/lists/arm-kernel/msg846093.html
> 
> I think we should disable the HS-DDR mode for A64 / H6 like it's done
> for H5 and not disable board per board until the issue is resolved.

I'm not opposed to that on principle, but "it doesn't work on some
board" is not a proper justification to do so. It does on some others,
so surely there's more to it and this would just paper over whatever
issue we have instead of properly fixing it.

> If you want to disable only for your board you can set in your
> device-tree: mmc-hs200-1_8v; This will switch to HS200 mode without
> using the HS-DDR mode.

Sigh. Can we at least work on a fix instead of providing terrible
workarounds?

Maxime
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