[Intel-gfx] [PATCH] drm/i915/glk: Fix DSI "*ERROR* ULPS is still active" messages

[Chauhan, Madhav]

> -----Original Message-----
> From: Conselvan De Oliveira, Ander
> Sent: Friday, April 28, 2017 1:32 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Conselvan De Oliveira, Ander <ander.conselvan.de.oliveira at intel.com>;
> Deepak M <m.deepak at intel.com>; Chauhan, Madhav
> <madhav.chauhan at intel.com>; Nikula, Jani <jani.nikula at intel.com>; Vetter,
> Daniel <daniel.vetter at intel.com>; Jani Nikula <jani.nikula at linux.intel.com>;
> drm-intel-fixes at lists.freedesktop.org
> Subject: [PATCH] drm/i915/glk: Fix DSI "*ERROR* ULPS is still active"
> messages
> 
> The sequence in glk_dsi_device_ready() enters ULPS then waits until it is
> *not* active to then disable it. The correct sequence according to the spec is
> to enter ULPS then wait until the GLK_ULPS_NOT_ACTIVE bit is zero, i.e., ULPS
> is active, and then disable ULPS.
> 
> Fixing the codition gets rid of the following spurious error messages:

Please correct the typo error to "condition", otherwise looks good.
Thanks for catching this.

> 
> [drm:glk_dsi_device_ready [i915]] *ERROR* ULPS is still active
> 
> Fixes: 4644848369c0 ("drm/i915/glk: Add MIPIIO Enable/disable sequence")
> Cc: Deepak M <m.deepak at intel.com>
> Cc: Madhav Chauhan <madhav.chauhan at intel.com>
> Cc: Jani Nikula <jani.nikula at intel.com>
> Cc: Daniel Vetter <daniel.vetter at intel.com>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: intel-gfx at lists.freedesktop.org
> Cc: <drm-intel-fixes at lists.freedesktop.org>
> Signed-off-by: Ander Conselvan de Oliveira
> <ander.conselvan.de.oliveira at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dsi.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c
> b/drivers/gpu/drm/i915/intel_dsi.c
> index 3ffe8b1..fc0ef49 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -410,11 +410,10 @@ static void glk_dsi_device_ready(struct
> intel_encoder *encoder)
>  		val |= (ULPS_STATE_ENTER | DEVICE_READY);
>  		I915_WRITE(MIPI_DEVICE_READY(port), val);
> 
> -		/* Wait for ULPS Not active */
> +		/* Wait for ULPS active */
>  		if (intel_wait_for_register(dev_priv,
> -				MIPI_CTRL(port), GLK_ULPS_NOT_ACTIVE,
> -				GLK_ULPS_NOT_ACTIVE, 20))
> -			DRM_ERROR("ULPS is still active\n");
> +				MIPI_CTRL(port), GLK_ULPS_NOT_ACTIVE, 0,
> 20))
> +			DRM_ERROR("ULPS not active\n");
> 
>  		/* Exit ULPS */
>  		val = I915_READ(MIPI_DEVICE_READY(port));
> --
> 2.9.3