linux-kernel - [PATCH 1/2] drm: mali-dp: Remove mclk rate management

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Date:   Mon,  6 Mar 2017 15:51:56 +0000
From:   Liviu Dudau <Liviu.Dudau@....com>
To:     David Airlie <airlied@...ux.ie>,
        Brian Starkey <brian.starkey@....com>,
        Mali DP Maintainers <malidp@...s.arm.com>
Cc:     DRI devel <dri-devel@...ts.freedesktop.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Mihail Atanassov <mihail.atanassov@....com>
Subject: [PATCH 1/2] drm: mali-dp: Remove mclk rate management

From: Mihail Atanassov <mihail.atanassov@....com>

The rate of mclk depends on the use-case. If no downscaling is required,
then mclk == pxlclk is a valid option; with downscaling however, the
rate at which mclk runs determines how much a plane can be downscaled
before composition. This is a system integration + power management
issue that is more suited to firmware rather than this driver.

Signed-off-by: Mihail Atanassov <mihail.atanassov@....com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@....com>
---
 drivers/gpu/drm/arm/malidp_crtc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/arm/malidp_crtc.c b/drivers/gpu/drm/arm/malidp_crtc.c
index 08e6a71f5d05..294b53697334 100644
--- a/drivers/gpu/drm/arm/malidp_crtc.c
+++ b/drivers/gpu/drm/arm/malidp_crtc.c
@@ -63,8 +63,7 @@ static void malidp_crtc_enable(struct drm_crtc *crtc)
 
 	clk_prepare_enable(hwdev->pxlclk);
 
-	/* mclk needs to be set to the same or higher rate than pxlclk */
-	clk_set_rate(hwdev->mclk, crtc->state->adjusted_mode.crtc_clock * 1000);
+	/* We rely on firmware to set mclk to a sensible level. */
 	clk_set_rate(hwdev->pxlclk, crtc->state->adjusted_mode.crtc_clock * 1000);
 
 	hwdev->modeset(hwdev, &vm);
-- 
2.11.1