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From:   Heiko =?ISO-8859-1?Q?St=FCbner?= <heiko@sntech.de>
To:     Marc Zyngier <marc.zyngier@arm.com>
Cc:     linux-rockchip@lists.infradead.org,
        Thierry Escande <thierry.escande@collabora.com>,
        Archit Taneja <architt@codeaurora.org>,
        Inki Dae <inki.dae@samsung.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Sandy Huang <hjc@rock-chips.com>,
        Sean Paul <seanpaul@chromium.org>,
        David Airlie <airlied@linux.ie>,
        Tomasz Figa <tfiga@chromium.org>,
        Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Zain Wang <wzz@rock-chips.com>, Lin Huang <hl@rock-chips.com>,
        Douglas Anderson <dianders@chromium.org>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Yakir Yang <ykk@rock-chips.com>,
        =?ISO-8859-1?Q?=D8rjan?= Eide <orjan.eide@arm.com>,
        Mark Yao <mark.yao@rock-chips.com>,
        Haixia Shi <hshi@chromium.org>
Subject: Re: [PATCH v3 05/43] drm/bridge: analogix_dp: Don't power bridge in analogix_dp_bind
Date:   Wed, 28 Feb 2018 15:56:12 +0100
Message-ID: <7345252.P7zEYUIqsL@diego>
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References: <20180130202913.28724-1-thierry.escande@collabora.com> <2776489.2p7NH6SBud@diego> <2c89da60-3c54-a8db-db9d-6079c51ed29d@arm.com>
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Am Mittwoch, 28. Februar 2018, 15:54:30 CET schrieb Marc Zyngier:
> On 28/02/18 14:37, Heiko St?bner wrote:
> > Am Dienstag, 30. Januar 2018, 21:28:35 CET schrieb Thierry Escande:
> >> From: zain wang <wzz@rock-chips.com>
> >> 
> >> The bridge does not need to be powered in analogix_dp_bind(), so
> >> remove the calls to pm_runtime_get()/phy_power_on()/analogix_dp_init_dp()
> >> as well as their power-off counterparts.
> >> 
> >> Cc: St?phane Marchesin <marcheu@chromium.org>
> >> Signed-off-by: zain wang <wzz@rock-chips.com>
> >> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> >> [the patch originally just removed the power_on portion, seanpaul removed
> >> the power off code as well as improved the commit message]
> >> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> >> Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
> >> ---
> >> 
> >>  drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 10 ----------
> >>  1 file changed, 10 deletions(-)
> >> 
> >> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> >> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index
> >> cb5e18d6ba04..1477ea9ba85d 100644
> >> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> >> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> >> @@ -1382,11 +1382,6 @@ analogix_dp_bind(struct device *dev, struct
> >> drm_device *drm_dev,
> >> 
> >>  	pm_runtime_enable(dev);
> >> 
> >> -	pm_runtime_get_sync(dev);
> >> -	phy_power_on(dp->phy);
> >> -
> >> -	analogix_dp_init_dp(dp);
> >> -
> >> 
> >>  	ret = devm_request_threaded_irq(&pdev->dev, dp->irq,
> >>  	
> >>  					analogix_dp_hardirq,
> >>  					analogix_dp_irq_thread,
> > 
> > Not 100% sure here, as the driver has the request-irq + disable-irq hack
> > here. So a pending interrupt could possibly fire between request and
> > disable.
> > 
> > Right now the block should be on, but can it still handle such an irq
> > when the power is removed?
> 
> Probably not (see below).
> 
> > So before removing the power here, we might want something
> > similar to what Marc posted for the vop [0] for the analogix-dp?
> 
> You can do that trick only if the interrupt is not shared. In the VOP
> case, it is shared with the IOMMU, which makes it more... interesting.

Yep, which is why I mentioned it, as the dp-irq should not be shared
I'd think :-)


Heiko