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 at suse.com> Signed-off-by: Wu Fengguang <fengguang.wu at intel.com> --- drivers/gpu/drm/i915/i915_reg.h | 12 ++++++++++++ drivers/gpu/drm/i915/intel_display.c | 8 +++++++- 2 files changed, 19 insertions(+), 1 deletion(-) > I've tried to apply this patch but it has a conflict in i915_reg.h (with > the SOL reset stuff). Care to rebase and resend? Also, git patches as > produced by git format-patch highly preferred. Daniel, this is now based on linux-next. I use quilt, hope it also works for you :) --- linux-next.orig/drivers/gpu/drm/i915/i915_reg.h 2012-01-07 20:47:34.000000000 +0800 +++ linux-next/drivers/gpu/drm/i915/i915_reg.h 2012-01-29 12:37:31.000000000 +0800 @@ -3742,4 +3742,16 @@ */ #define GEN7_SO_WRITE_OFFSET(n) (0x5280 + (n) * 4) +#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-next.orig/drivers/gpu/drm/i915/intel_display.c 2012-01-29 12:23:17.000000000 +0800 +++ linux-next/drivers/gpu/drm/i915/intel_display.c 2012-01-29 12:37:31.000000000 +0800 @@ -6072,15 +6072,18 @@ 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; } @@ -6088,6 +6091,7 @@ 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)); @@ -6107,7 +6111,9 @@ 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 */ + } else + I915_WRITE(aud_config, 0); if (intel_eld_uptodate(connector, aud_cntrl_st2, eldv,