Re: radeonfb lockup in .28-rc (bisected)

From: Benjamin Herrenschmidt
Date: Mon Oct 27 2008 - 20:07:32 EST


On Mon, 2008-10-27 at 19:45 -0400, James Cloos wrote:
> Commit b1ee26bab1 breaks radeonfb on my inspiron 8100 (P3-M with a
> Mobility M7 LW [7500] (1002:4c57 1028:00e6)).
>
> The boot is OK until init(8) starts; after init outputs its version info
> it calls rc(8), which starts by setting the fb font. At that point any
> kernel with b1ee26bab1 locks hard. The cursor stops flashing, magic
> sysrq stops working and the fan starts up after a few seconds. (I can't
> tell whether it is the CPU or the GPU that heats up.)
>
> If it is relevant, I use a 10x20 font, so the font change means the
> console converts from 200x75, 8x16 to 160x60, 10x20.

Annoying... Either I'm doing something wrong (which is always possible)
or we're hitting yet another fancy ATI bug (the M7 generation is known
to be pretty bad in that area).

First, let's see if it's related to the imageblit. Can you re-apply the
reverted patch and apply this little hack on top :

Index: linux-work/drivers/video/aty/radeon_accel.c
===================================================================
--- linux-work.orig/drivers/video/aty/radeon_accel.c 2008-10-28 11:01:49.000000000 +1100
+++ linux-work/drivers/video/aty/radeon_accel.c 2008-10-28 11:01:57.000000000 +1100
@@ -252,6 +252,7 @@ void radeonfb_imageblit(struct fb_info *
if (!image->width || !image->height)
return;

+#if 0
/* We only do 1 bpp color expansion for now */
if (info->flags & FBINFO_HWACCEL_DISABLED || image->depth != 1)
goto fallback;
@@ -275,6 +276,7 @@ void radeonfb_imageblit(struct fb_info *
return;

fallback:
+#endif
radeon_engine_idle(rinfo);

cfb_imageblit(info, image);

And let me know if that makes it not lockup.

Cheers,
Ben.


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