linux-kernel - Re: [PATCH 3/3 v2] drm/i915: hot plug/unplug notification to HDMI audio driver

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Date:	Thu, 24 Nov 2011 17:38:26 +0800
From:	Wu Fengguang <fengguang.wu@...el.com>
To:	Keith Packard <keithp@...thp.com>
Cc:	Takashi Iwai <tiwai@...e.de>,
	"Wang, Zhenyu Z" <zhenyu.z.wang@...el.com>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3 v2] drm/i915: hot plug/unplug notification to HDMI
 audio driver

On Thu, Nov 24, 2011 at 03:26:49AM +0800, Keith Packard wrote:
> On Wed, 23 Nov 2011 16:29:58 +0800, Wu Fengguang <fengguang.wu@...el.com> wrote:
> 
> > What I need is a hot plug hook that knows whether the monitor is
> > plugged or removed, which is only possible if the hook is called
> > after ->detect().
> 
> That would be mode_set to tell you that the monitor is in use, and the
> disable function to tell you when the monitor is no longer in use.
> 
> You do not want to do anything to the hardware in the hot_plug paths;
> those are strictly informative; telling user space which connectors are
> present.

Thanks a lot for the tips! When doing things in the right path, I got
a much reduced patch :-)

Due to DP being a bit more tricky than HDMI and no convenient DP test
environment, I'll have to delay the DP part to next week...

Thanks,
Fengguang
---
Subject: drm/i915: HDMI hot remove notification to audio driver
Date: Fri Nov 11 13:49:04 CST 2011

On HDMI monitor hot remove, clear SDVO_AUDIO_ENABLE accordingly, so that
the audio driver will receive hot plug events and take action to refresh
its device state and ELD contents.

The cleared SDVO_AUDIO_ENABLE bit needs to be restored to prevent losing
HDMI audio after DPMS on.

CC: Wang Zhenyu <zhenyu.z.wang@...el.com>
Signed-off-by: Wu Fengguang <fengguang.wu@...el.com>
---
 drivers/gpu/drm/i915/intel_dp.c   |    4 +++-
 drivers/gpu/drm/i915/intel_hdmi.c |    8 ++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

--- linux.orig/drivers/gpu/drm/i915/intel_hdmi.c	2011-11-24 17:11:38.000000000 +0800
+++ linux/drivers/gpu/drm/i915/intel_hdmi.c	2011-11-24 17:15:03.000000000 +0800
@@ -269,6 +269,10 @@ static void intel_hdmi_dpms(struct drm_e
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(encoder);
 	u32 temp;
+	u32 enable_bits = SDVO_ENABLE;
+
+	if (intel_hdmi->has_audio)
+		enable_bits |= SDVO_AUDIO_ENABLE;
 
 	temp = I915_READ(intel_hdmi->sdvox_reg);
 
@@ -281,9 +285,9 @@ static void intel_hdmi_dpms(struct drm_e
 	}
 
 	if (mode != DRM_MODE_DPMS_ON) {
-		temp &= ~SDVO_ENABLE;
+		temp &= ~enable_bits;
 	} else {
-		temp |= SDVO_ENABLE;
+		temp |= enable_bits;
 	}
 
 	I915_WRITE(intel_hdmi->sdvox_reg, temp);
--
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