On Thu, 2006-11-02 at 16:26 -0500, Phillip Susi wrote:
> Arjan van de Ven wrote:
> > that's for the 32 bit boundary. THe problem is that there are 31, 30, 28
> > and 26 bit devices as well, and those are in more trouble, and will
> > eventually fall back to GFP_DMA (inside the x86 PCI code; the driver
> > just uses the pci dma allocation routines) if they can't get suitable
> > memory otherwise....
> >
> > It's all nice in theory. But then there is the reality that not all
> > devices are nice pci device that implement the entire spec;)
> >
>
> Right, but doesn't the bounce/allocation routine take as a parameter the
> limit that the device can handle? If the device can handle 28 bit
> addresses, then the kernel should not limit it to only 24 bits.
you're right in theory, but the kernel only has a few pools of memory
available, but not at every bit boundary. there is a 32 bit pool
(GFP_DMA32) on some, a 30-ish bit pool (GFP_KERNEL) on others, and a 24
bit pool (GFP_DMA) with basically nothing inbetween.
--
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
