From mboxrd@z Thu Jan 1 00:00:00 1970 From: Damien Lespiau Subject: Re: [PATCH] drm/i915: Don't trust the DP_DETECT bit for eDP ports on CHV Date: Mon, 13 Oct 2014 19:03:51 +0100 Message-ID: <20141013180351.GA10112@strange.ger.corp.intel.com> References: <1412872635-534-1-git-send-email-ville.syrjala@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTP id 8AAC789DA8 for ; Mon, 13 Oct 2014 11:07:08 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1412872635-534-1-git-send-email-ville.syrjala@linux.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: ville.syrjala@linux.intel.com Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Thu, Oct 09, 2014 at 07:37:15PM +0300, ville.syrjala@linux.intel.com wro= te: > From: Ville Syrj=E4l=E4 > = > 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=3D84265 > Signed-off-by: Ville Syrj=E4l=E4 Reviewed-by: Damien Lespiau -- = 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_devi= ce *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 > = > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx