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From: "Andreas Färber" <andreas.faerber@web.de>
To: Jan Kiszka <jan.kiszka@web.de>
Cc: "Hervé Poussineau" <hpoussin@reactos.org>,
	qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] MMIO coalescing of the i82378 bridge
Date: Sat, 23 Jun 2012 14:46:07 +0200	[thread overview]
Message-ID: <4FE5BA8F.7050405@web.de> (raw)
In-Reply-To: <4FE58C20.4020803@web.de>

Hi Jan,

Am 23.06.2012 11:28, schrieb Jan Kiszka:
> just stumbled over the memory_region_set_coalescing in pci_i82378_init:
> What ISA devices are affected by this? It looks a bit strange to me as
> the MMIO requests are apparently mapped on PIO requests, and we don't
> have PIO coalescing on x86. Depending on the target device on PREP, this
> may have some unexpected side effects. Or is only framebuffer memory
> addressed this way?

I only remember touching that line to rebase it onto either Memory API
or QOM. The i82378 is the sole PCI-ISA bridge so all ISA devices will be
affected by it, which is pretty much everything except VGA iirc.
The upcoming pc87312(?) Super I/O also would be attached to it,
replacing some of the bogus I/O in the current "prep" machine.

I'm not familiar with what this option affects. What unexpected side
effects would you expect? :)

Regards,
Andreas

  reply	other threads:[~2012-06-23 12:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-23  9:28 [Qemu-devel] MMIO coalescing of the i82378 bridge Jan Kiszka
2012-06-23 12:46 ` Andreas Färber [this message]
2012-06-23 12:53   ` Jan Kiszka

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