Re: [Dri-devel] PPC Lockup (ati-pcigart-branch)

Come on, someone has to know what's going on here... :)

For the Linux/PPC developers: the purpose of this code is to walk a virtual
memory range and look up the page struct for each page. I spent some time on
the train this morning trying to figure out what might be wrong but couldn't
find anything obvious.

I've narrowed down the problem by modifying the code like this:

        for ( i = entry->handle, j = 0 ; j < pages ; i += PAGE_SIZE, j++ ) {
                printk("i: %08lx\n", i);
                pgd = pgd_offset_k( i );
                printk("pgd: %08lx\n", pgd);
                pmd = pmd_offset( pgd, i );
                printk("pmd: %08lx\n", pmd);
                pte = pte_offset( pmd, i );
                printk("pte: %08lx\n", pte);

                entry->pagelist[j]= pte_page( *pte );
                printk("Checkpoint 5\n");
                SetPageReserved( entry->pagelist[j] );
                printk("Checkpoint 6\n");

                if ( j < 16 ) {
                        DRM_DEBUG("0x%08lx (page %lu) => 0x%08lx\n",
                                  i, j,
                                  (unsigned
long)entry->pagelist[j]->virtual);
                }
        }

[...]

[drm] drm_sg_alloc
i: ca292000
pgd: c014dca0
pmd: c014dca0
pte: 00000a48
Oops: kernel access of bad area, sig: 11

Looking at pgd/pmd, pte seems fishy for a pointer. Any reason why this code
shouldn't work on PPC?


Michel


--
Earthling Michel Dänzer (MrCooper)    \   Debian GNU/Linux (powerpc) developer
CS student, Free Software enthusiast   \        XFree86 and DRI project member

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