Re: USB mass storage and ARM cache coherency

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

 



Am Mittwoch, 24. Februar 2010 03:48:09 schrieb Benjamin Herrenschmidt:
> On Fri, 2010-02-19 at 21:53 +0100, Oliver Neukum wrote:
> > Am Freitag, 19. Februar 2010 18:36:51 schrieb Catalin Marinas:
> > > If a page is already mapped in user space, flush_dcache_page() on ARM
> > > does the flushing rather than deferring it to update_mmu_cache(). The
> > > PIO HCD drivers, however, don't call flush_dcache_page(). Is it possible
> > > that the HCD could transfer data into a page cache page already mapped
> > > in user space? My understanding is that the scenario above is possible.
> > 
> > Yes, video drivers do that. 
> 
> In which case it would be up to the video driver to call
> flush_dcache_page() (though if it's v4l you are talking about, maybe it
> might make sense to push it into the v4l layer itself).

I don't know. The issue seems quite complex. It would seem better to
centralize it as far as practical. Do you have a wrapper drivers could
call?

	Regards
		Oliver
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

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

  Powered by Linux