Thread (14 messages) flat view 14 messages, 4 authors, 2006-11-27

Re: 2.6.19-rc5: Geode GX frame buffer takes 13 seconds to initialize

From: James Simmons <hidden>
Date: 2006-11-21 15:07:25

Thank you :-) If this works it will save me alot of trouble.

On Mon, 20 Nov 2006, Jordan Crouse wrote:
On 20/11/06 16:47 -0600, Ben Gardner wrote:
quoted
I tracked it down to the memset_io() call in gxfb_core.c that clears
all the video memory.

It take 12.5 seconds to memset() a mere 16,384 Kibyte of memory.
That seems a bit strange to me.

What's stranger is the time it takes to clear the fb memory:
The first 4 MB clear in 0.01 s each.
The last 12MB are SLOW.
 
Hmmm - thats interesting.  One thing about the current gxfb driver is that
it assumes a 16Mb framebuffer, which may or may not be what you have, since 
the amount of memory that is assigned to the graphics engine is configurable.

Its possible that you only have 4Mb of memory assigned to the graphics
engine, and that memsetting further is out being subtractively decoded on
the PCI bus and going nowhere slowly.

The attached patch queries the BIOS for the true amount of memory that
is configured.  The patch has been kicking around in the Geode git tree and 
-mm for a while so it should be sane.  Give it a try and see if it helps.

Jordan
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