Re: mmc vs highmem, was: Re: [PATCH 2/2] blk-mq: ensure a q_usage_counter reference is held when splitting bios

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Wed, Jan 24, 2024 at 1:55 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:

> > So I am seeing if these can be excluded from the "most omap2plus
> > systems" list.
>
> Unfortunately excluding Nokia n8x0 would turn the omap2plus
> defconfig into an omap3plus_defconfig effectively.

I did like this:

@@ -135,7 +135,7 @@ config ARCH_OMAP2PLUS_TYPICAL
        bool "Typical OMAP configuration"
        default y
        select AEABI
-       select HIGHMEM
+       select HIGHMEM if !SOC_OMAP2420

Effectively disabling HIGHMEM when using omap2plus_defconfig.

If we want all systems supported, we just apply this at the expense
of highmem for OMAP 2430, OMAP3 and OMAP4 and the

We can then either

- Disable SOC_OMAP2420 in omap2plus_defconfig (I made a
  patch for this) turning it
  into an omap3plus_defconfig as you say

or

- Actually add a new defconfig named omap3plus_defconfig
  with highmem enabled but SOC_OMAP2420 disabled.

I don't know which option is the lesser evil ... it's a bit hairy.

(A third option would be to reexamine runtime restriction options...)

Yours,
Linus Walleij