Re: 2.6.10-mm2 solved

From: Brice Goglin
Date: Mon Jan 10 2005 - 05:18:47 EST


Dave Airlie a écrit :
I still only see "agp_backend_acquire failed on atomic read".

do you see how many atomic inc and atomic decs there is?

send me the full dmesg...
thanks,
Dave.

The agp_in_use field of the bridge structure is never initialized.
That's the reason why atomic_read fails to read 0.

In vanilla, the bridge is allocated as a static global variable, and
thus initialized to 0 at init. In -mm, the bridge is kmalloc'ed, and
thus not initialized.

The attached patch fixes it and solves my problem (when combined with
http://lkml.org/lkml/2005/1/7/377). DRM is back with good performance.

Regards
Brice
--- linux-mm/drivers/char/agp/backend.c.orig 2005-01-10 10:36:13.000000000 +0100
+++ linux-mm/drivers/char/agp/backend.c 2005-01-10 10:34:35.000000000 +0100
@@ -235,6 +235,8 @@
if (!bridge)
return NULL;

+ atomic_set(&bridge->agp_in_use, 0);
+
if (list_empty(&agp_bridges))
agp_bridge = bridge;