linux-kernel - Re: [PATCH] drm/i915: set AUD_CONFIG N_value

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Message-ID: <20120110054519.GA27257@localhost>
Date:	Tue, 10 Jan 2012 13:45:19 +0800
From:	Wu Fengguang <fengguang.wu@...el.com>
To:	Keith Packard <keithp@...thp.com>
Cc:	LKML <linux-kernel@...r.kernel.org>, Takashi Iwai <tiwai@...e.de>,
	Michal Marek <mmarek@...e.com>,
	"intel-gfx@...ts.freedesktop..." <intel-gfx@...ts.freedesktop.org>,
	Robert Lemaire <rlemaire@...e.com>
Subject: Re: [PATCH] drm/i915: set AUD_CONFIG N_value_index for DisplayPort

On Mon, Jan 09, 2012 at 09:22:47AM -0800, Keith Packard wrote:
> On Mon, 9 Jan 2012 21:17:17 +0800, Wu Fengguang <fengguang.wu@...el.com> wrote:
> 
> > +#define IBX_AUD_CONFIG_A		0xe2000
> > +#define CPT_AUD_CONFIG_A		0xe5000
> 
> These register addresses match the docs.
> 
> > +		I915_WRITE(aud_config, 1 << 29); /* N value index, 0x1 = DP */
> 
> Please don't use constants here, instead add #defines for all of the
> bits in this new register, in case someone else needs to use the
> register later.

OK. Updated patch to use macro as follows.

> Do we also need to program the pixel clock values in this register?

The pixel clock value is only for HDMI. I'd not touch this as long as
it works fine ;)

Thanks,
Fengguang
---
Subject: drm/i915: set AUD_CONFIG N_value_index for DisplayPort
Date: Fri Jan 06 14:41:31 CST 2012

It should be programmed to "0" for HDMI or "1" for DisplayPort.

This enables DisplayPort audio for

- HP EliteBook 8460p
  (whose BIOS does not set the N_value_index bit for us)

- DisplayPort monitor hot plugged after boot
  (otherwise most BIOS will fill the N_value_index bit for us)

Tested-by: Robert Lemaire <rlemaire@...e.com>
Signed-off-by: Wu Fengguang <fengguang.wu@...el.com>
---
 drivers/gpu/drm/i915/i915_reg.h      |   12 ++++++++++++
 drivers/gpu/drm/i915/intel_display.c |    5 +++++
 2 files changed, 17 insertions(+)

--- linux.orig/drivers/gpu/drm/i915/i915_reg.h	2012-01-07 23:11:10.000000000 +0800
+++ linux/drivers/gpu/drm/i915/i915_reg.h	2012-01-10 13:20:17.000000000 +0800
@@ -3582,4 +3582,16 @@
 #define CPT_AUD_CNTL_ST_A		0xE50B4
 #define CPT_AUD_CNTRL_ST2		0xE50C0
 
+#define IBX_AUD_CONFIG_A			0xe2000
+#define CPT_AUD_CONFIG_A			0xe5000
+#define   AUD_CONFIG_N_VALUE_INDEX		(1 << 29)
+#define   AUD_CONFIG_N_PROG_ENABLE		(1 << 28)
+#define   AUD_CONFIG_UPPER_N_SHIFT		20
+#define   AUD_CONFIG_UPPER_N_VALUE		(0xff << 20)
+#define   AUD_CONFIG_LOWER_N_SHIFT		4
+#define   AUD_CONFIG_LOWER_N_VALUE		(0xfff << 4)
+#define   AUD_CONFIG_PIXEL_CLOCK_HDMI_SHIFT	16
+#define   AUD_CONFIG_PIXEL_CLOCK_HDMI		(0xf << 16)
+#define   AUD_CONFIG_DISABLE_NCTS		(1 << 3)
+
 #endif /* _I915_REG_H_ */
--- linux.orig/drivers/gpu/drm/i915/intel_display.c	2012-01-07 23:11:10.000000000 +0800
+++ linux/drivers/gpu/drm/i915/intel_display.c	2012-01-10 13:23:25.000000000 +0800
@@ -5908,15 +5908,18 @@ static void ironlake_write_eld(struct dr
 	uint32_t i;
 	int len;
 	int hdmiw_hdmiedid;
+	int aud_config;
 	int aud_cntl_st;
 	int aud_cntrl_st2;
 
 	if (HAS_PCH_IBX(connector->dev)) {
 		hdmiw_hdmiedid = IBX_HDMIW_HDMIEDID_A;
+		aud_config = IBX_AUD_CONFIG_A;
 		aud_cntl_st = IBX_AUD_CNTL_ST_A;
 		aud_cntrl_st2 = IBX_AUD_CNTL_ST2;
 	} else {
 		hdmiw_hdmiedid = CPT_HDMIW_HDMIEDID_A;
+		aud_config = CPT_AUD_CONFIG_A;
 		aud_cntl_st = CPT_AUD_CNTL_ST_A;
 		aud_cntrl_st2 = CPT_AUD_CNTRL_ST2;
 	}
@@ -5924,6 +5927,7 @@ static void ironlake_write_eld(struct dr
 	i = to_intel_crtc(crtc)->pipe;
 	hdmiw_hdmiedid += i * 0x100;
 	aud_cntl_st += i * 0x100;
+	aud_config += i * 0x100;
 
 	DRM_DEBUG_DRIVER("ELD on pipe %c\n", pipe_name(i));
 
@@ -5943,6 +5947,7 @@ static void ironlake_write_eld(struct dr
 	if (intel_pipe_has_type(crtc, INTEL_OUTPUT_DISPLAYPORT)) {
 		DRM_DEBUG_DRIVER("ELD: DisplayPort detected\n");
 		eld[5] |= (1 << 2);	/* Conn_Type, 0x1 = DisplayPort */
+		I915_WRITE(aud_config, AUD_CONFIG_N_VALUE_INDEX); /* 0x1 = DP */
 	}
 
 	if (intel_eld_uptodate(connector,
--
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