I found this patch here : http://www.vdr-portal.de/board/thread.php?threadid=57529&threadview=0&hilight=&hilightuser=0&page=1


it would be nice to have that in upstream and also to be able to enable or disable it with "csync" fbset option


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diff -ur linux-2.6.18.3.org/drivers/video/aty/radeon_base.c linux-2.6.18.3/drivers/video/aty/radeon_base.c
--- linux-2.6.18.3.org/drivers/video/aty/radeon_base.c 2006-08-23 23:16:33.000000000 +0200
+++ linux-2.6.18.3/drivers/video/aty/radeon_base.c 2006-12-11 22:11:56.000000000 +0100
@@ -683,6 +683,9 @@
rinfo-> pll.ppll_max = BIOS_IN32(pll_info_block + 0x16);

printk(KERN_INFO "radeonfb: Retrieved PLL infos from BIOS\n");
+printk(KERN_INFO "radeonfb: disregarding BIOS ppll_min of %d\n", rinfo-> pll.ppll_min);
+rinfo->pll.ppll_min = 12000;
+printk(KERN_INFO "radeonfb: using ppll_min of %d instead\n", rinfo->pll.ppll_min);
goto found;
}

@@ -1660,6 +1663,13 @@
CRTC_CRT_ON;
}

+/*printk(KERN_INFO "radeonfb: vmode requested 0x%x\n", mode->vmode);*/
+#define CRTC_CSYNC_EN (1 << 4)
+if (mode->vmode & FB_VMODE_INTERLACED) {
+ newmode->crtc_gen_cntl |= CRTC_INTERLACE_EN | CRTC_CSYNC_EN;
+}
+/*printk(KERN_INFO "radeonfb: crtc_gen_cntl 0x%x\n", newmode->crtc_gen_cntl);*/
+
newmode->dac_cntl = /* INREG(DAC_CNTL) | */ DAC_MASK_ALL | DAC_VGA_ADR_EN |
DAC_8BIT_EN;

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