[PATCH 3.18 22/33] drm/gma500/psb: Actually use VBT mode when it is found

Greg Kroah-Hartman
2017-06-05T16:19:58Z

From: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>

commit 82bc9a42cf854fdf63155759c0aa790bd1f361b0 upstream.

With LVDS we were incorrectly picking the pre-programmed mode instead of
the prefered mode provided by VBT. Make sure we pick the VBT mode if
one is provided. It is likely that the mode read-out code is still wrong
but this patch fixes the immediate problem on most machines.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78562
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170418114332.12183-1-patrik.r.jakobsson@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/gma500/psb_intel_lvds.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)

--- a/drivers/gpu/drm/gma500/psb_intel_lvds.c
+++ b/drivers/gpu/drm/gma500/psb_intel_lvds.c
@@ -783,20 +783,23 @@ void psb_intel_lvds_init(struct drm_devi
if (scan->type & DRM_MODE_TYPE_PREFERRED) {
mode_dev->panel_fixed_mode =
drm_mode_duplicate(dev, scan);
+ DRM_DEBUG_KMS("Using mode from DDC\n");
goto out; /* FIXME: check for quirks */
}
}

/* Failed to get EDID, what about VBT? do we need this? */
- if (mode_dev->vbt_mode)
+ if (dev_priv->lfp_lvds_vbt_mode) {
mode_dev->panel_fixed_mode =
- drm_mode_duplicate(dev, mode_dev->vbt_mode);
+ drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);

- if (!mode_dev->panel_fixed_mode)
- if (dev_priv->lfp_lvds_vbt_mode)
- mode_dev->panel_fixed_mode =
- drm_mode_duplicate(dev,
- dev_priv->lfp_lvds_vbt_mode);
+ if (mode_dev->panel_fixed_mode) {
+ mode_dev->panel_fixed_mode->type |=
+ DRM_MODE_TYPE_PREFERRED;
+ DRM_DEBUG_KMS("Using mode from VBT\n");
+ goto out;
+ }
+ }

/*
* If we didn't get EDID, try checking if the panel is already turned
@@ -813,6 +816,7 @@ void psb_intel_lvds_init(struct drm_devi
if (mode_dev->panel_fixed_mode) {
mode_dev->panel_fixed_mode->type |=
DRM_MODE_TYPE_PREFERRED;
+ DRM_DEBUG_KMS("Using pre-programmed mode\n");
goto out; /* FIXME: check for quirks */
}
}