From: Stephen Boyd <sboyd@codeaurora.org>
To: Archit Taneja <architt@codeaurora.org>
Cc: linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v2 2/2] drm/msm: Set CLK_IGNORE_UNUSED flag for PLL clocks
Date: Thu, 27 Oct 2016 16:58:43 -0700 [thread overview]
Message-ID: <20161027235843.GG26139@codeaurora.org> (raw)
In-Reply-To: <1477549635-21104-1-git-send-email-architt@codeaurora.org>
On 10/27, Archit Taneja wrote:
> The DSI/HDMI PLLs in MSM require resources like interface clocks, power
> domains to be enabled before we can access their registers.
>
> The clock framework doesn't have a mechanism at the moment where we can
> tie such resources to a clock, so we make sure that the KMS driver enables
> these resources whenever a PLL is expected to be in use.
>
> One place where we can't ensure the resource dependencies are met is when
> the clock framework tries to disable unused clocks. The KMS driver doesn't
> know when the clock framework calls the is_enabled clk_op, and hence can't
> enable interface clocks/power domains beforehand.
>
> We set the CLK_IGNORE_UNUSED flag for PLL clocks for now. This needs to be
> revisited, since bootloaders can enable display, and we would want to
> disable the PLL clocks if there isn't a display driver using them.
>
> Cc: Stephen Boyd <sboyd@codeaurora.org>
> Signed-off-by: Archit Taneja <architt@codeaurora.org>
> ---
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
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prev parent reply other threads:[~2016-10-27 23:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-25 6:47 [PATCH 0/2] drm/msm: Fixes for issues seen on DB410c Archit Taneja
2016-10-25 6:47 ` [PATCH 1/2] drm/msm/dsi: Queue HPD helper work in attach/detach callbacks Archit Taneja
2016-10-25 6:48 ` [PATCH 2/2] drm/msm: Don't provide 'is_enabled' PLL clk_ops Archit Taneja
2016-10-25 20:28 ` Stephen Boyd
2016-10-26 7:36 ` Archit Taneja
2016-10-27 6:27 ` [PATCH v2 2/2] drm/msm: Set CLK_IGNORE_UNUSED flag for PLL clocks Archit Taneja
2016-10-27 23:58 ` Stephen Boyd [this message]
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