| Message ID | 20170202170307.24484-3-tiwai@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, 02 Feb 2017 18:02:15 +0100, Takashi Iwai wrote: > > The audio chicken bit (register offset 0x62f38) seems required to make > DP audio working on some machines. At least, on Dell Wyse 3040, I > failed to get the audio unless this bit is set once. > > Strangely, the bit seems necessary only once, and it persists after > that, even some power-off cycles. The register is supposedly > write-only, so it's no evidence whether the bit keeps effect > persistently. But, judging from the experiment, it looks enough to > set it up once at the device initialization. > > The patch is basically a cut from the original patch by Pierre-Louis > Bossart. > > Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> > Signed-off-by: Takashi Iwai <tiwai@suse.de> Sorry, this one is just a resend by mistake (I forgot to clean up while sending the other patch series). Please disregard. Takashi
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 4e24ba0cdbe8..4f15a3dc6d98 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -2062,6 +2062,9 @@ enum skl_disp_power_wells { #define I915_HDMI_LPE_AUDIO_SIZE 0x1000 /* DisplayPort Audio w/ LPE */ +#define VLV_AUD_CHICKEN_BIT_REG _MMIO(VLV_DISPLAY_BASE + 0x62F38) +#define VLV_CHICKEN_BIT_DBG_ENABLE (1 << 0) + #define _VLV_AUD_PORT_EN_B_DBG (VLV_DISPLAY_BASE + 0x62F20) #define _VLV_AUD_PORT_EN_C_DBG (VLV_DISPLAY_BASE + 0x62F30) #define _VLV_AUD_PORT_EN_D_DBG (VLV_DISPLAY_BASE + 0x62F34) diff --git a/drivers/gpu/drm/i915/intel_lpe_audio.c b/drivers/gpu/drm/i915/intel_lpe_audio.c index d3ffe0012692..3ba2799e93bd 100644 --- a/drivers/gpu/drm/i915/intel_lpe_audio.c +++ b/drivers/gpu/drm/i915/intel_lpe_audio.c @@ -248,6 +248,13 @@ static int lpe_audio_setup(struct drm_i915_private *dev_priv) goto err_free_irq; } + /* enable chicken bit; at least this is required for Dell Wyse 3040 + * with DP outputs (but only sometimes by some reason!) + */ + I915_WRITE(VLV_AUD_CHICKEN_BIT_REG, + I915_READ(VLV_AUD_CHICKEN_BIT_REG) | + VLV_CHICKEN_BIT_DBG_ENABLE); + return 0; err_free_irq: irq_free_desc(dev_priv->lpe_audio.irq);
The audio chicken bit (register offset 0x62f38) seems required to make DP audio working on some machines. At least, on Dell Wyse 3040, I failed to get the audio unless this bit is set once. Strangely, the bit seems necessary only once, and it persists after that, even some power-off cycles. The register is supposedly write-only, so it's no evidence whether the bit keeps effect persistently. But, judging from the experiment, it looks enough to set it up once at the device initialization. The patch is basically a cut from the original patch by Pierre-Louis Bossart. Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> --- drivers/gpu/drm/i915/i915_reg.h | 3 +++ drivers/gpu/drm/i915/intel_lpe_audio.c | 7 +++++++ 2 files changed, 10 insertions(+)