linux-kernel - Re: [PATCH v3 05/43] drm/bridge: analogix_dp: Don't power bridge in analogix_dp

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Date:   Wed, 28 Feb 2018 15:37:40 +0100
From:   Heiko Stübner <heiko@...ech.de>
To:     linux-rockchip@...ts.infradead.org,
        Marc Zyngier <marc.zyngier@....com>
Cc:     Thierry Escande <thierry.escande@...labora.com>,
        Archit Taneja <architt@...eaurora.org>,
        Inki Dae <inki.dae@...sung.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Sandy Huang <hjc@...k-chips.com>,
        Sean Paul <seanpaul@...omium.org>,
        David Airlie <airlied@...ux.ie>,
        Tomasz Figa <tfiga@...omium.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Zain Wang <wzz@...k-chips.com>, Lin Huang <hl@...k-chips.com>,
        Douglas Anderson <dianders@...omium.org>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Yakir Yang <ykk@...k-chips.com>,
        Ørjan Eide <orjan.eide@....com>,
        Mark Yao <mark.yao@...k-chips.com>,
        Haixia Shi <hshi@...omium.org>
Subject: Re: [PATCH v3 05/43] drm/bridge: analogix_dp: Don't power bridge in analogix_dp_bind

Am Dienstag, 30. Januar 2018, 21:28:35 CET schrieb Thierry Escande:
> From: zain wang <wzz@...k-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: Stéphane Marchesin <marcheu@...omium.org>
> Signed-off-by: zain wang <wzz@...k-chips.com>
> Signed-off-by: Caesar Wang <wxt@...k-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@...omium.org>
> Signed-off-by: Thierry Escande <thierry.escande@...labora.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?

So before removing the power here, we might want something
similar to what Marc posted for the vop [0] for the analogix-dp?


Heiko

[0] https://patchwork.kernel.org/patch/10210513/