Re: [PATCH v2 3/3] x86/quirks: Add early quirk to reset Apple AirPort card
From: Ingo Molnar
Date: Sun Jun 12 2016 - 07:49:13 EST
* Lukas Wunner <lukas@xxxxxxxxx> wrote:
> The solution is to reset the card on boot by writing to a reset bit in
> its mmio space. This must be done as an early quirk and not as a plain
> vanilla PCI quirk to successfully combat memory corruption by DMAed
> packets: Matthew Garrett found out in 2012 that the packets are written
> to EfiBootServicesData memory (http://mjg59.dreamwidth.org/11235.html).
> This type of memory is made available to the page allocator by
> efi_free_boot_services(). [...]
Btw., would it also make sense to *not* free those pages by default, if firmware
can occasionally corrupt them? What memory size are we talking about?
Thanks,
Ingo