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Subject: Re: [PATCH v3] drm/i915: Re-init lspcon after HPD if lspcon probe
 failed
From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
In-Reply-To: <20191224084251.28414-1-kai.heng.feng@canonical.com>
Date:   Mon, 6 Jan 2020 16:35:26 +0800
Cc:     ville.syrjala@linux.intel.com, swati2.sharma@intel.com,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
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To:     jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com,
        rodrigo.vivi@intel.com, airlied@linux.ie, daniel@ffwll.ch
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Hi Jani,

> On Dec 24, 2019, at 16:42, Kai-Heng Feng <kai.heng.feng@canonical.com> wrote:
> 
> On HP 800 G4 DM, if HDMI cable isn't plugged before boot, the HDMI port
> becomes useless and never responds to cable hotplugging:
> [    3.031904] [drm:lspcon_init [i915]] *ERROR* Failed to probe lspcon
> [    3.031945] [drm:intel_ddi_init [i915]] *ERROR* LSPCON init failed on port D
> 
> Seems like the lspcon chip on the system in question only gets powered
> after the cable is plugged.
> 
> So let's call lspcon_init() dynamically to properly initialize the
> lspcon chip and make HDMI port work.

Do you have any further suggestion for this patch?

Kai-Heng

> 
> Closes: https://gitlab.freedesktop.org/drm/intel/issues/203
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
> v3:
> - Make sure it's handled under long HPD case.
> 
> v2: 
> - Move lspcon_init() inside of intel_dp_hpd_pulse().
> 
> drivers/gpu/drm/i915/display/intel_dp.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index fe31bbfd6c62..a72c9c041c60 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -6573,6 +6573,7 @@ enum irqreturn
> intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> {
> 	struct intel_dp *intel_dp = &intel_dig_port->dp;
> +	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> 
> 	if (long_hpd && intel_dig_port->base.type == INTEL_OUTPUT_EDP) {
> 		/*
> @@ -6593,7 +6594,12 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
> 		      long_hpd ? "long" : "short");
> 
> 	if (long_hpd) {
> -		intel_dp->reset_link_params = true;
> +		if (intel_dig_port->base.type == INTEL_OUTPUT_DDI &&
> +		    HAS_LSPCON(dev_priv) && !intel_dig_port->lspcon.active)
> +			lspcon_init(intel_dig_port);
> +		else
> +			intel_dp->reset_link_params = true;
> +
> 		return IRQ_NONE;
> 	}
> 
> -- 
> 2.17.1
>