Re: [PATCH v2] drm/i915: Fix drm:intel_enable_lvds ERROR message in kernel log

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 19 Apr 2018, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Florent Flament <contact@florentflament.com>
>
> Fix `[drm:intel_enable_lvds] *ERROR* timed out waiting for panel to
> power on` in kernel log at boot time.
>
> Toshiba Satellite Z930 laptops needs between 1 and 2 seconds to power
> on its screen during Intel i915 DRM initialization. This currently
> results in a `[drm:intel_enable_lvds] *ERROR* timed out waiting for
> panel to power on` message appearing in the kernel log during boot
> time and when stopping the machine.
>
> This change increases the timeout of the `intel_enable_lvds` function
> from 1 to 2 seconds, letting enough time for the Satellite 930 LCD
> screen to power on, and suppressing the error message from the kernel
> log.

Please update the commit message to match what the patch actually does
now, instead of hiding it in braces below. With that (and can be done
while pushing),

Reviewed-by: Jani Nikula <jani.nikula@intel.com>


>
> This patch has been successfully tested on Linux 4.14 running on a
> Toshiba Satellite Z930.
>
> Signed-off-by: Florent Flament <contact@florentflament.com>
> [vsyrjala: bump the timeout from 2 to 5 seconds to match the DP
>  code and properly cover the max hw timeout of ~4 seconds, and
>  drop the comment about the specific machine since this is not
>  a particulary surprising issue, nor specific to that one machine]
> Cc: Pavel Petrovic <ppetrovic@acm.org>
> Cc: Sérgio M. Basto <sergio@serjux.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103414
> References: https://bugzilla.kernel.org/show_bug.cgi?id=57591
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_lvds.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
> index d35d2d50f595..8691c86f579c 100644
> --- a/drivers/gpu/drm/i915/intel_lvds.c
> +++ b/drivers/gpu/drm/i915/intel_lvds.c
> @@ -326,7 +326,8 @@ static void intel_enable_lvds(struct intel_encoder *encoder,
>  
>  	I915_WRITE(PP_CONTROL(0), I915_READ(PP_CONTROL(0)) | PANEL_POWER_ON);
>  	POSTING_READ(lvds_encoder->reg);
> -	if (intel_wait_for_register(dev_priv, PP_STATUS(0), PP_ON, PP_ON, 1000))
> +
> +	if (intel_wait_for_register(dev_priv, PP_STATUS(0), PP_ON, PP_ON, 5000))
>  		DRM_ERROR("timed out waiting for panel to power on\n");
>  
>  	intel_panel_enable_backlight(pipe_config, conn_state);

-- 
Jani Nikula, Intel Open Source Technology Center
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