Re: [PATCH] drm/gma500/cdv: Check vbt config bits when detecting lvds panels

Hans de Goede <hdegoede@xxxxxxxxxx> · Mon, 29 Apr 2019 16:44:07 +0200

Hi,

On 22-04-19 19:54, Patrik Jakobsson wrote:
On Sun, Apr 21, 2019 at 8:46 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:

Hi,

On 16-04-19 13:46, Patrik Jakobsson wrote:
Some machines have an lvds child device in vbt even though a panel is
not attached. To make detection more reliable we now also check the lvds
config bits available in the vbt.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1665766
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@xxxxxxxxx>
Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>

The reporter of https://bugzilla.redhat.com/show_bug.cgi?id=1665766
just got back to me and he confirms that this patch fixes the
false-positive LVDS panel detection on his NAS, without needing
a DMI blacklist.

So it looks like this patch indeed is a better fix then my initial
DMI blacklist approach and from my pov this patch is ready to
go upstream.

Thanks Hans, can I add your review tag?

Erm, then I would need to actually review it first ... done:

Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>

Regards,

Hans


---
   drivers/gpu/drm/gma500/cdv_intel_lvds.c | 3 +++
   drivers/gpu/drm/gma500/intel_bios.c     | 3 +++
   drivers/gpu/drm/gma500/psb_drv.h        | 1 +
   3 files changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/gma500/cdv_intel_lvds.c b/drivers/gpu/drm/gma500/cdv_intel_lvds.c
index de9531caaca0..9c8446184b17 100644
--- a/drivers/gpu/drm/gma500/cdv_intel_lvds.c
+++ b/drivers/gpu/drm/gma500/cdv_intel_lvds.c
@@ -594,6 +594,9 @@ void cdv_intel_lvds_init(struct drm_device *dev,
       int pipe;
       u8 pin;

+     if (!dev_priv->lvds_enabled_in_vbt)
+             return;
+
       pin = GMBUS_PORT_PANEL;
       if (!lvds_is_present_in_vbt(dev, &pin)) {
               DRM_DEBUG_KMS("LVDS is not present in VBT\n");
diff --git a/drivers/gpu/drm/gma500/intel_bios.c b/drivers/gpu/drm/gma500/intel_bios.c
index 63bde4e86c6a..e019ea271ffc 100644
--- a/drivers/gpu/drm/gma500/intel_bios.c
+++ b/drivers/gpu/drm/gma500/intel_bios.c
@@ -436,6 +436,9 @@ parse_driver_features(struct drm_psb_private *dev_priv,
       if (driver->lvds_config == BDB_DRIVER_FEATURE_EDP)
               dev_priv->edp.support = 1;

+     dev_priv->lvds_enabled_in_vbt = driver->lvds_config != 0;
+     DRM_DEBUG_KMS("LVDS VBT config bits: 0x%x\n", driver->lvds_config);
+
       /* This bit means to use 96Mhz for DPLL_A or not */
       if (driver->primary_lfp_id)
               dev_priv->dplla_96mhz = true;
diff --git a/drivers/gpu/drm/gma500/psb_drv.h b/drivers/gpu/drm/gma500/psb_drv.h
index 941b238bdcc9..bc608ddc3bd1 100644
--- a/drivers/gpu/drm/gma500/psb_drv.h
+++ b/drivers/gpu/drm/gma500/psb_drv.h
@@ -537,6 +537,7 @@ struct drm_psb_private {
       int lvds_ssc_freq;
       bool is_lvds_on;
       bool is_mipi_on;
+     bool lvds_enabled_in_vbt;
       u32 mipi_ctrl_display;

       unsigned int core_freq;

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