Linux ARM-MSM sub-architecture
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From: Eric Anholt <eric-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org>
To: Rob Clark <robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Cc: linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	freedreno-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Subject: Re: [PATCH] drm/msm/dsi: workaround for display enabled by bootloader
Date: Tue, 17 Oct 2017 13:16:14 -0700	[thread overview]
Message-ID: <874lqxttrl.fsf@anholt.net> (raw)
In-Reply-To: <20171017143918.12518-1-robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>


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Rob Clark <robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> writes:

> Bootloader enabled display, when the driver is built-in (rather than a
> module loaded after CCF/genpd disable "unused" clocks/powerdomains)
> causes problems since the driver thinks the clocks are off, but in fact
> they are on.  This causes (for example) clk_set_rate() to fail.
>
> A better solution would be to support display handover from bootloader,
> but that will require some CCF+genpd changes before that is possible.
> So until then, we need this workaround.

Hmm.  Couldn't the clk_set_rate() just turn off the clock and then make
the rate change when there are no refs on the clk currently?

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  parent reply	other threads:[~2017-10-17 20:16 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-17 14:38 [PATCH] drm/msm/dsi: workaround for display enabled by bootloader Rob Clark
     [not found] ` <20171017143918.12518-1-robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-10-17 20:16   ` Eric Anholt [this message]
     [not found]     ` <874lqxttrl.fsf-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org>
2017-10-17 20:33       ` Rob Clark

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