Re: [PATCH] usb: devio: fix mmap() on non-coherent DMA architectures

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, Aug 05, 2019 at 05:17:13PM +0200, Greg KH wrote:
> On Fri, Aug 02, 2019 at 10:57:00AM -0700, Gavin Li wrote:
> > usbfs mmap() looks like it was introduced for 4.6 in commit
> > f7d34b445abc, so it should probably be backported to 4.9 and onwards.
> > This issue has been present since the introduction of the feature.
> > 
> > One sidenote: this patch will cause the following warning on x86 due
> > to dmap_mmap_coherent() trying to map normal memory in as uncached:
> > 
> > x86/PAT: ... map pfn RAM range req uncached-minus for [mem
> > 0x77b000000-0x77b210fff], got write-back
> > 
> > This warning is harmless, as x86 is DMA coherent and the memory gets
> > correctly mapped in as write-back. I will submit a patch to the DMA
> > mapping team to eliminate this warning.
> 
> Let me know what the git commit id of that patch is, I will wait for it
> to hit the tree before adding this one.

Dropping this patch from my queue now, please feel free to resend when
you have refreshed it against the latest tree.

thanks,

greg k-h



[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux