Re: radeon: screen garbled after page allocator change, was: Re: [patch v2 3/3] mm: page_alloc: fair zone allocator policy

[Thomas Schwinge]

Hi!

On Sun, 27 Apr 2014 15:55:29 -0400, Jerome Glisse <j.glisse@xxxxxxxxx> wrote:
> If my ugly patch works does this quirk also work ?

Unfortunately they both don't; see my other email,
<http://news.gmane.org/find-root.php?message_id=%3C87sioxq3rx.fsf%40schwinge.name%3E>.


Also, the quirk patch resulted in a NULL pointer dereference in
pci_find_ht_capability+0x4/0x30, which I hacked around as follows:

diff --git drivers/pci/quirks.c drivers/pci/quirks.c
index f025867..33aaad2 100644
--- drivers/pci/quirks.c
+++ drivers/pci/quirks.c
@@ -2452,6 +2452,8 @@ u64 pci_ht_quirk_dma_32bit_only(struct pci_dev *dev, u64 mask)
 		struct pci_dev *bridge = bus->self;
 		int pos;
 
+		if (!bridge)
+			goto skip;
 		pos = pci_find_ht_capability(bridge, HT_CAPTYPE_SLAVE);
 		if (pos) {
 			int ctrl_off;
@@ -2472,6 +2474,7 @@ u64 pci_ht_quirk_dma_32bit_only(struct pci_dev *dev, u64 mask)
 				return 0xffffffff;
 			}
 		}
+	skip:
 		bus = bus->parent;
 	} while (bus);
 	return mask;

If needed, I can try to capture more data, but someone who has knowledge
of PCI bus architecture and Linux kernel code (so, not me), might
probably already see what's wrong.


GrÃÃe,
 Thomas

Attachment: pgp5cSJGQtRae.pgp
Description: PGP signature