On Mon, 27 Feb 2017 11:22:32 +0100
Hans de Goede wrote:
> On some devices only MIPI PORT C is used, in this case checking the
> MIPI PORT A CTRL AFE_LATCHOUT bit (there is no such bit for PORT C
> on VLV/CHT) will result in false positive "DSI LP not going Low" errors
> as this checks the PORT A clk status.
>
> In case both ports are used we have already checked the AFE_LATCHOUT
> bit when going through the for_each_dsi_port() loop for PORT A and
> checking the same bit again for PORT C is a no-op.
>
> BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=97061
> Signed-off-by: Hans de Goede
Reviewed-by: Bob Paauwe
> ---
> drivers/gpu/drm/i915/intel_dsi.c | 8 +---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c
> b/drivers/gpu/drm/i915/intel_dsi.c
> index 1fcce2c..185b8eb 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -458,10 +458,12 @@ static void intel_dsi_clear_device_ready(struct
> intel_encoder *encoder)
> ULPS_STATE_ENTER);
> usleep_range(2000, 2500);
>
> - /* Wait till Clock lanes are in LP-00 state for MIPI Port A
> - * only. MIPI Port C has no similar bit for checking
> + /*
> + * On VLV/CHV, wait till Clock lanes are in LP-00 state for MIPI
> + * Port A only. MIPI Port C has no similar bit for checking.
>*/
> - if (intel_wait_for_register(dev_priv,
> + if ((IS_GEN9_LP(dev_priv) || port == PORT_A) &&
> + intel_wait_for_register(dev_priv,
> port_ctrl, AFE_LATCHOUT, 0,
> 30))
> DRM_ERROR("DSI LP not going Low\n");
--
--
Bob Paauwe
bob.j.paa...@intel.com
IOTG / PED Software Organization
Intel Corp. Folsom, CA
(916) 356-6193
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