Messages in this thread |  | | | Date | Sat, 20 Mar 2004 20:44:44 +0100 (CET) | | From | Jaroslav Kysela <> | | Subject | Re: can device drivers return non-ram via vm_ops->nopage? |
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On Sat, 20 Mar 2004, Russell King wrote:
> It is well known that virt_to_page() is only valid on virtual addresses > which correspond to kernel direct mapped RAM pages, and undefined on > everything else. Unfortunately, ALSA has been using it with > pci_alloc_consistent() for a long time, and this behaviour is what > makes ALSA broken. The fact it works on x86 is merely incidental.
It works on PPC as well (at least we have no error reports).
> If ALSA wants this functionality, the ALSA people should ideally have > put their requirements forward during the 2.5 development cycle so the > problem could be addressed.
Yes, I'm sorry about that, but the ->nopage usage was requested by Jeff Garzik and we're not gurus for the VM stuff. Because we're probably first starting using of this mapping scheme, it resulted to problems.
> However, luckily in this instance, it is not a big problem to solve. > It just requires time to sort through all the abstraction layers upon > abstraction layers which ALSA has. > > - and I'm doing exactly this, right now. Be patient. -
Thanks a lot.
Jaroslav
----- Jaroslav Kysela <perex@suse.cz> Linux Kernel Sound Maintainer ALSA Project, SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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