drm/nv40: add LVDS table quirk for Dell Latitude D620

Should fix:
 https://bugzilla.redhat.com/show_bug.cgi?id=505132
 https://bugzilla.redhat.com/show_bug.cgi?id=543091
 https://bugzilla.redhat.com/show_bug.cgi?id=530425
 https://bugs.edge.launchpad.net/ubuntu/+source/xserver-xorg-video-nouveau/
 +bug/539730

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_bios.c b/drivers/gpu/drm/nouveau/nouveau_bios.c
index 075eb894648f..ad6c2d4520ae 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bios.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bios.c
@@ -3659,6 +3659,21 @@ int nouveau_bios_parse_lvds_table(struct drm_device *dev, int pxclk, bool *dl, b
                 break;
         }
 
+        /* Dell Latitude D620 reports a too-high value for the dual-link
+         * transition freq, causing us to program the panel incorrectly.
+         *
+         * It doesn't appear the VBIOS actually uses its transition freq
+         * (90000kHz), instead it uses the "Number of LVDS channels" field
+         * out of the panel ID structure (http://www.spwg.org/).
+         *
+         * For the moment, a quirk will do :)
+         */
+        if ((dev->pdev->device == 0x01d7) &&
+            (dev->pdev->subsystem_vendor == 0x1028) &&
+            (dev->pdev->subsystem_device == 0x01c2)) {
+                bios->fp.duallink_transition_clk = 80000;
+        }
+
         /* set dual_link flag for EDID case */
         if (pxclk && (chip_version < 0x25 || chip_version > 0x28))
                 bios->fp.dual_link = (pxclk >= bios->fp.duallink_transition_clk);