Geode sc2200 vga

[Christer Weinigel]

Christer Weinigel <christer at weinigel.se> writes:

> <confession time>
> 
> Ok, I downloaded the linux4.tv driver again and tried it on my SC2200
> board and I can't get it to work either.  Very strange, since I had it
> working with LinuxBIOS a couple of months ago.  It might be that I had
> to turn on some clock or PLL by hand.  
> 
> </confession time>
> 
> Oh well, I'll try to see if I can find a backup of the kernel I used
> then and see if I can get it running again.

Following up to myself... Backups are a good thing :-)

This patch initializes a few registers on the SC2200 that the geodefb
code from linux4.tv doesn't seem to touch.  The values I'm storing
into the registers are read from a system running with the XpressROM
BIOS.  Now I can see the penguin when booting Linux from LinuxBIOS.
The timing for the video mode seems strange, my monitor has some
trouble syncing on this signal, but at least I get some kind of video.
I guess that something similar is needed to get video from a CS5530
based system.

I think I'll give up on this for the moment, I'm not all that
interested in video myself, I just wanted to know why it didn't work
when I knew that I had had it running before.  If anyone needs video
to work on a SC2200, make a dump of the F4BAR1 registers and the GCR
registers and compare them with a working system (booted from
XPressROM) and look in the data sheets to see if the differences seem
significant.  

  /Christer (off to sleep)

diff -ur linux-2.4.19/drivers/video/geode/geodefb.c.orig linux-2.4.19/drivers/video/geode/geodefb.c
--- linux-2.4.19/drivers/video/geode/geodefb.c.orig	Tue Apr 10 17:09:01 2001
+++ linux-2.4.19/drivers/video/geode/geodefb.c	Mon Jan  6 23:27:31 2003
@@ -182,6 +182,8 @@
 #include <linux/init.h>
 #include <linux/devfs_fs_kernel.h>
 
+#include <linux/pci.h>
+
 #include <asm/io.h>
 #include <asm/mtrr.h>
 
@@ -1350,6 +1352,36 @@
         return(-EBUSY);
     }
 
+    if (1)			/* wingel */
+    {
+	struct pci_dev *pdev;
+	u8 *video;
+
+	if ((pdev = pci_find_device(PCI_VENDOR_ID_NS, 
+				    PCI_DEVICE_ID_NS_SCx200_VIDEO,
+				    NULL)) == NULL) {
+	    printk("can't find scx200\n");
+	} else if (!(video = ioremap(pci_resource_start(pdev, 1), 0x1000))) {
+	    printk(KERN_ERR "unable to ioremap video\n");
+	} else {
+	    writel(0x00001000, gfx_virt_regptr + 0x8308); /* disable timing generator */
+
+	    writel(0x0020030f, video + 0x04);
+	    writel(0x00001000, video + 0x28);
+	    writel(0x0070e00c, video + 0x2c);
+	    
+	    writel(0x00000100, video + 0x44);
+	    writel(0x00000156, video + 0x48);
+	    writel(0x00060000, video + 0x4c);
+	    writel(0x00ffffff, video + 0x50);
+	    writel(0x00ffffff, video + 0x54);
+	    
+	    writel(0x1000102f, gfx_virt_regptr + 0x8308);
+
+	    iounmap(video);
+	}
+    }
+
     geode_create_galdevice();
     
     strcpy(gen.info.modename, geodefb_name);


-- 
"Just how much can I get away with and still go to heaven?"

Freelance consultant specializing in device driver programming for Linux 
Christer Weinigel <christer at weinigel.se>  http://www.weinigel.se