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From:   Jani Nikula <jani.nikula@linux.intel.com>
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>,
        joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com,
        airlied@linux.ie, daniel@ffwll.ch
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,
        Kai-Heng Feng <kai.heng.feng@canonical.com>
Subject: Re: [PATCH] drm/i915: Re-init lspcon after HPD if lspcon probe failed
In-Reply-To: <20191223095604.17453-1-kai.heng.feng@canonical.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
References: <20191223095604.17453-1-kai.heng.feng@canonical.com>
Date:   Mon, 23 Dec 2019 12:11:15 +0200
Message-ID: <87eewvwdvg.fsf@intel.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, 23 Dec 2019, 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.
>
> Closes: https://gitlab.freedesktop.org/drm/intel/issues/203
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
>  drivers/gpu/drm/i915/display/intel_hotplug.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c
> index fc29046d48ea..e2862e36d0bf 100644
> --- a/drivers/gpu/drm/i915/display/intel_hotplug.c
> +++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
> @@ -28,6 +28,7 @@
>  #include "i915_drv.h"
>  #include "intel_display_types.h"
>  #include "intel_hotplug.h"
> +#include "intel_lspcon.h"
>  
>  /**
>   * DOC: Hotplug
> @@ -336,6 +337,8 @@ static void i915_digport_work_func(struct work_struct *work)
>  			continue;
>  
>  		dig_port = enc_to_dig_port(&encoder->base);
> +		if (HAS_LSPCON(dev_priv) && !dig_port->lspcon.active)
> +			lspcon_init(dig_port);

The whole digport work function is platform and encoder agnostic, this
call has no place in here.

One alternative is intel_dp_hpd_pulse().


BR,
Jani.


>  
>  		ret = dig_port->hpd_pulse(dig_port, long_hpd);
>  		if (ret == IRQ_NONE) {

-- 
Jani Nikula, Intel Open Source Graphics Center