On Mon, 13 Oct 2014, Damien Lespiau <damien.lesp...@intel.com> wrote:
> On Thu, Oct 09, 2014 at 07:37:15PM +0300, ville.syrj...@linux.intel.com wrote:
>> From: Ville Syrjälä <ville.syrj...@linux.intel.com>
>>
>> On CHV the display DDC pins may be muxed to an alternate function if
>> there's no need for DDC on a specific port, which is the case for eDP
>> ports since there's no way to plug in a DP++ HDMI dongle.
>>
>> This causes problems when trying to determine if the port is present
>> since the the DP_DETECTED bit is the latched state of the DDC SDA pin
>> at boot. If the DDC pins are muxed to an alternate function the bit
>> may indicate that the port isn't present.
>>
>> To work around this look at the VBT as well as the DP_DETECTED bit
>> to determine if we should attempt registering an eDP port. Do this
>> only for ports B and C since port D doesn't support eDP (no PPS/BLC).
>>
>> In theory someone could also wire up a normal DP port w/o DDC lines.
>> That would just mean that simple DP++ HDMI dongles wouldn't work
>> on such a port. With this change we would still fail to register
>> such DP ports. But let's hope no one wires their board in such a way,
>> and if they do we can extend the VBT checks to cover normal DP ports
>> as well.
>>
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84265
>> Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
>
> Reviewed-by: Damien Lespiau <damien.lesp...@intel.com>
Pushed to drm-intel-next-fixes, thanks for the patch and review.
BR,
Jani.
>
> --
> Damien
>
>> ---
>> drivers/gpu/drm/i915/intel_display.c | 33 +++++++++++++++++++++------------
>> 1 file changed, 21 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_display.c
>> b/drivers/gpu/drm/i915/intel_display.c
>> index b5476dc..d6fc469 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -12280,27 +12280,36 @@ static void intel_setup_outputs(struct drm_device
>> *dev)
>> if (I915_READ(PCH_DP_D) & DP_DETECTED)
>> intel_dp_init(dev, PCH_DP_D, PORT_D);
>> } else if (IS_VALLEYVIEW(dev)) {
>> - if (I915_READ(VLV_DISPLAY_BASE + GEN4_HDMIB) & SDVO_DETECTED) {
>> + /*
>> + * The DP_DETECTED bit is the latched state of the DDC
>> + * SDA pin at boot. However since eDP doesn't require DDC
>> + * (no way to plug in a DP->HDMI dongle) the DDC pins for
>> + * eDP ports may have been muxed to an alternate function.
>> + * Thus we can't rely on the DP_DETECTED bit alone to detect
>> + * eDP ports. Consult the VBT as well as DP_DETECTED to
>> + * detect eDP ports.
>> + */
>> + if (I915_READ(VLV_DISPLAY_BASE + GEN4_HDMIB) & SDVO_DETECTED)
>> intel_hdmi_init(dev, VLV_DISPLAY_BASE + GEN4_HDMIB,
>> PORT_B);
>> - if (I915_READ(VLV_DISPLAY_BASE + DP_B) & DP_DETECTED)
>> - intel_dp_init(dev, VLV_DISPLAY_BASE + DP_B,
>> PORT_B);
>> - }
>> + if (I915_READ(VLV_DISPLAY_BASE + DP_B) & DP_DETECTED ||
>> + intel_dp_is_edp(dev, PORT_B))
>> + intel_dp_init(dev, VLV_DISPLAY_BASE + DP_B, PORT_B);
>>
>> - if (I915_READ(VLV_DISPLAY_BASE + GEN4_HDMIC) & SDVO_DETECTED) {
>> + if (I915_READ(VLV_DISPLAY_BASE + GEN4_HDMIC) & SDVO_DETECTED)
>> intel_hdmi_init(dev, VLV_DISPLAY_BASE + GEN4_HDMIC,
>> PORT_C);
>> - if (I915_READ(VLV_DISPLAY_BASE + DP_C) & DP_DETECTED)
>> - intel_dp_init(dev, VLV_DISPLAY_BASE + DP_C,
>> PORT_C);
>> - }
>> + if (I915_READ(VLV_DISPLAY_BASE + DP_C) & DP_DETECTED ||
>> + intel_dp_is_edp(dev, PORT_C))
>> + intel_dp_init(dev, VLV_DISPLAY_BASE + DP_C, PORT_C);
>>
>> if (IS_CHERRYVIEW(dev)) {
>> - if (I915_READ(VLV_DISPLAY_BASE + CHV_HDMID) &
>> SDVO_DETECTED) {
>> + if (I915_READ(VLV_DISPLAY_BASE + CHV_HDMID) &
>> SDVO_DETECTED)
>> intel_hdmi_init(dev, VLV_DISPLAY_BASE +
>> CHV_HDMID,
>> PORT_D);
>> - if (I915_READ(VLV_DISPLAY_BASE + DP_D) &
>> DP_DETECTED)
>> - intel_dp_init(dev, VLV_DISPLAY_BASE +
>> DP_D, PORT_D);
>> - }
>> + /* eDP not supported on port D, so don't check VBT */
>> + if (I915_READ(VLV_DISPLAY_BASE + DP_D) & DP_DETECTED)
>> + intel_dp_init(dev, VLV_DISPLAY_BASE + DP_D,
>> PORT_D);
>> }
>>
>> intel_dsi_init(dev);
>> --
>> 2.0.4
>>
>> _______________________________________________
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>> Intel-gfx@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
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--
Jani Nikula, Intel Open Source Technology Center
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