Messages in this thread | | | Subject | Re: [Bug #12608] 2.6.29-rc powerpc G5 Xorg legacy_mem regression | From | Benjamin Herrenschmidt <> | Date | Sat, 07 Feb 2009 13:51:12 +1100 |
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> I still don't understand the point of this legacy_mem file at all, > and why X should want to mmap it, if it works so well when it's > thus divorced from reality. But I won't worry my pretty little > head over it any further - please don't waste your time trying > to explain it to me!
VGA memory hole :-) ie, text mode & fonts
Ben.
> Thanks, > Hugh > > > > > Index: linux-work/arch/powerpc/kernel/pci-common.c > > =================================================================== > > --- linux-work.orig/arch/powerpc/kernel/pci-common.c 2009-02-06 16:23:36.000000000 +1100 > > +++ linux-work/arch/powerpc/kernel/pci-common.c 2009-02-06 16:30:32.000000000 +1100 > > @@ -561,8 +561,21 @@ int pci_mmap_legacy_page_range(struct pc > > (unsigned long long)(offset + size - 1)); > > > > if (mmap_state == pci_mmap_mem) { > > - if ((offset + size) > hose->isa_mem_size) > > - return -ENXIO; > > + /* Hack alert ! > > + * > > + * Because X is lame and can fail starting if it gets an error trying > > + * to mmap legacy_mem (instead of just moving on without legacy memory > > + * access) we fake it here by giving it anonymous memory, effectively > > + * behaving just like /dev/zero > > + */ > > + if ((offset + size) > hose->isa_mem_size) { > > + printk(KERN_DEBUG > > + "Process %s (pid:%d) mapped non-existing PCI legacy memory for 0%04x:%02x\n", > > + current->comm, current->pid, pci_domain_nr(bus), bus->number); > > + if (vma->vm_flags & VM_SHARED) > > + return shmem_zero_setup(vma); > > + return 0; > > + } > > offset += hose->isa_mem_phys; > > } else { > > unsigned long io_offset = (unsigned long)hose->io_base_virt - _IO_BASE;
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