Messages in this thread | | | Subject | Re: [Dri-devel] Re: [Linux-fbdev-devel] DRM and pci_driver conversion | From | (Eric W. Biederman) | Date | 27 Oct 2003 08:10:16 -0700 |
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Linus Torvalds <torvalds@osdl.org> writes:
> On Sat, 25 Oct 2003, Egbert Eich wrote: > > > > Speaking of XFree86: when I developed the PCI resource stuff in > > XFree86 I was trying to get support from kernel folks to get the > > appropriate user space interfaces into the kernel. When I got > > nowhere I decided to do everything myself. > > There won't be any "user space interfaces". There are perfectly good > in-kernel interfaces, and anybody who needs them needs to be in kernel > space. Ie the kernel interfaces are for kernel modules, not for user space > accesses.
Well almost. There is still one significant flaw in the kernel space stuff.
The BIOS can specify arbitrary regions as reserved in the E820 map and then a kernel driver can't use that region itself. This shows up in corner cases where the resource on the PCI device is a boolean rather than a general purpose thing. Particularly for mtd map drivers to allow flashing your ROM from linux this is a problem.
This is not required for 2.6.0 but it would be nice to actually be able to reliably reserve resources in kernel drivers.
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