Re: [PATCH v3 4/5] ARM: footbridge: limit CONFIG_ISA to CATS

On Sun, Sep 11, 2022, at 9:53 PM, Russell King (Oracle) wrote:

On Fri, Sep 09, 2022 at 10:57:48PM +0200, Arnd Bergmann wrote:

quoted

From: Arnd Bergmann <arnd@arndb.de>

The CONFIG_ISA option is only used for actual add-in cards, not
on-board devices. NetWinder has no hardware support for those,
and ebsa285 appears to not support them in Linux, as the XBUS
is not set up that way and there is no support for a PCI-ISA
bridge.

That is an incorrect assumption, but is still true as far as ISA
DMA is concerned.

The "Team" produced a PCI card with a PCI southbridge chip on, along
with ISAPNP devices. ISAPNP depends on CONFIG_ISA... That said, using
the "ESS ES1879 Plug and Play AudioDrive" on it requires ISA DMA, and
as DMA from the PCI southbridge causes the PCI bus to deadlock, it
probably doesn't matter.

However, what I'm pointing out is that the assertion that CONFIG_ISA
means ISA cards is not entirely correct with the creation of this
PCI southbridge card.

(This card gives me keyboard, mouse, serial etc ports which is its
main use in the machine.)

I dropped the patch now, and queued the rest of the series for
the 6.1 merge window.

      Arnd

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