Flaw of Auto-Configuration and VESA driver cause failure at hardy installation

[Liu, Wolke]

Hi all,

When I install Hardy desktop edtion (8.04 beta1), I failed and entered
the busybox interface instead of the graphic user guide.
I check the log file and it said 
(EE) Screen(s) found, but none have a usable configuration.
Fatal server error:
no screens found

The root cause I think is same as
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-vesa/+bug/1
74434/

I think it's a common issue. This bug frustrate user to install Ubuntu.
Now I can only install Ubuntu via alternate CD and update the driver by
myself. Then I can enter X.

The bug can be duplicated when the graphic card is only supported by
VESA driver and the monitor's hsync and vrefresh rate is just a value
that probed by X's auto configuration.

And the here is a patch from FC9 can fix the issue, can anybody help to
test it and add it to the current distribution before RC? Thanks

Patch contents:
--- xf86-video-vesa-1.3.0/src/vesa.c.jx	2007-01-30 10:31:32.000000000
-0500
+++ xf86-video-vesa-1.3.0/src/vesa.c	2007-01-30 10:56:15.000000000
-0500
@@ -638,8 +638,40 @@
 	xf86UnloadSubModule(pDDCModule);
     }
 
-    if ((pScrn->monitor->DDC = pVesa->monitor) != NULL)
-	xf86SetDDCproperties(pScrn, pVesa->monitor);
+    /* UNCLEAN */
+    do {
+	Bool had_cfg_ranges, have_ddc_ranges;
+
+	had_cfg_ranges = (pScrn->monitor->nHsync ||
pScrn->monitor->nVrefresh);
+	if ((pScrn->monitor->DDC = pVesa->monitor) != NULL)
+	    xf86SetDDCproperties(pScrn, pVesa->monitor);
+	have_ddc_ranges = (pScrn->monitor->nHsync ||
pScrn->monitor->nVrefresh);
+
+	if (have_ddc_ranges && !had_cfg_ranges) {
+	    int i;
+	    for (i = 0; i < DET_TIMINGS; i++) {
+		if (pVesa->monitor->det_mon[i].type == DS_RANGES)
+		    break;
+	    }
+	    if (i < DET_TIMINGS)
+		break;
+
+	    /*
+	     * DDC added ranges, but they're inferred from the modes,
not
+	     * copied from a range section.  So in the worst case, where
it's
+	     * not a range but a single frequency, stretch things out to
be
+	     * a range.  Panels with only one mode listed in DDC will
+	     * otherwise probably not match any VESA modes.  Hooray for
+	     * conformance.
+	     */
+	    if (pScrn->monitor->hsync[0].lo ==
pScrn->monitor->hsync[0].hi
+		 && pScrn->monitor->hsync[0].lo > 31.5)
+		pScrn->monitor->hsync[0].lo = 31.5;
+	    if (pScrn->monitor->vrefresh[0].lo ==
pScrn->monitor->vrefresh[0].hi
+		 && pScrn->monitor->vrefresh[0].lo > 50.0)
+		pScrn->monitor->vrefresh[0].lo = 50;
+	}
+    } while (0);
 
     xf86DrvMsgVerb(pScrn->scrnIndex, X_INFO, DEBUG_VERB,
 			"Searching for matching VESA mode(s):\n");


Regards,
Wolke