> -----Original Message----- > From: David Miller [mailto:davem@xxxxxxxxxxxxx] > Sent: Friday, March 20, 2015 1:24 PM > To: Koenig, Christian > Cc: Deucher, Alexander; dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] radeon: Do not directly dereference pointers to BIOS > area. > > From: Christian König <christian.koenig@xxxxxxx> > Date: Fri, 20 Mar 2015 10:38:32 +0100 > > > On 19.03.2015 17:29, David Miller wrote: > >> From: Christian König <christian.koenig@xxxxxxx> > >> Date: Thu, 19 Mar 2015 09:50:58 +0100 > >> > >>> In general I would say yes, but for this particular hardware it's a > >>> bit questionable to do so. > >>> > >>> For radeon hardware to work correctly the CPU access to the PCIE BARs > >>> should work even without using the specialized IO macros/functions, > >>> otherwise mapping VRAM CPU accessible isn't really possible. > >>> > >>> What's the background of the change? Some problems on a certain CPU > >>> platform? or just general cleanups? > >> It's an _iomem_ pointer, it's not a virtual address. > >> > >> Therefore it is illegal to dereference the pointer. > >> > >> The value is opaque and has values that only make sense when used > >> with the readb() et al. interfaces. > >> > >> This code is relying upon the fact that on x86 it happens to be > >> a virtual address, but this won't work on many other architectures. > > > > In this case I'm perfectly fine with it and the patch is Reviewed-by: > > Christian König <christian.koenig@xxxxxxx> > > > > Just wanted to make sure that you're not trying to get Radeon working > > on a platform which will never really support the necessary hardware > > features. > > I would like this to get merged via the Radeon DRM maintainer, thanks. Already added to my tree. Thanks! Alex _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
