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SubjectRe: [Intel-gfx] [PATCH 05/21] drm/i915: Check eDP power when doing aux channel communications
On Thu, Sep 29, 2011 at 06:09:37PM -0700, Keith Packard wrote:
> Verify that the eDP VDD is on, either with the panel being on or with
> the VDD force-on bit being set.
>
> This demonstrates that in many instances, VDD is not on when needed,
> which leads to failed EDID communications.
>
> Signed-off-by: Keith Packard <keithp@keithp.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 22 ++++++++++++++++++++++
> 1 files changed, 22 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 8ab2a88..3b29a6f 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -279,6 +279,24 @@ intel_hrawclk(struct drm_device *dev)
> }
> }
>
> +static void
> +intel_dp_check_edp(struct intel_dp *intel_dp)
> +{
> + struct drm_device *dev = intel_dp->base.base.dev;
> + struct drm_i915_private *dev_priv = dev->dev_private;
> + u32 pp_status, pp_control;
> + if (!is_edp(intel_dp))
> + return;
> + pp_status = I915_READ(PCH_PP_STATUS);
> + pp_control = I915_READ(PCH_PP_CONTROL);
> + if ((pp_status & PP_ON) == 0 && (pp_control & EDP_FORCE_VDD) == 0) {
> + WARN(1, "eDP powered off while attempting aux channel communication.\n");
> + DRM_DEBUG_KMS("Status 0x%08x Control 0x%08x\n",
> + pp_status,
> + I915_READ(PCH_PP_CONTROL));

Use pp_control instead of re-reading?

> + }
> +}
> +
> static int
> intel_dp_aux_ch(struct intel_dp *intel_dp,
> uint8_t *send, int send_bytes,
> @@ -295,6 +313,7 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
> uint32_t aux_clock_divider;
> int try, precharge;
>
> + intel_dp_check_edp(intel_dp);
> /* The clock divider is based off the hrawclk,
> * and would like to run at 2MHz. So, take the
> * hrawclk value and divide by 2 and use that

dp_aux_ch does the low-level io for the below, so either this one or the
below three hunks look a bit redundant.

> @@ -408,6 +427,7 @@ intel_dp_aux_native_write(struct intel_dp *intel_dp,
> int msg_bytes;
> uint8_t ack;
>
> + intel_dp_check_edp(intel_dp);
> if (send_bytes > 16)
> return -1;
> msg[0] = AUX_NATIVE_WRITE << 4;
> @@ -450,6 +470,7 @@ intel_dp_aux_native_read(struct intel_dp *intel_dp,
> uint8_t ack;
> int ret;
>
> + intel_dp_check_edp(intel_dp);
> msg[0] = AUX_NATIVE_READ << 4;
> msg[1] = address >> 8;
> msg[2] = address & 0xff;
> @@ -493,6 +514,7 @@ intel_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
> int reply_bytes;
> int ret;
>
> + intel_dp_check_edp(intel_dp);
> /* Set up the command byte */
> if (mode & MODE_I2C_READ)
> msg[0] = AUX_I2C_READ << 4;
> --
> 1.7.6.3
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48


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