[RFC 2/2] drm/tegra: Request memory bandwidth for the display controller

[Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>]

For now the amount requested is based solely on the current mode's refresh
rate.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
---
 drivers/gpu/drm/tegra/dc.c  | 11 +++++++++++
 drivers/gpu/drm/tegra/drm.h |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index ef40381..4bcf09b 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -683,6 +683,8 @@ static void tegra_crtc_disable(struct drm_crtc *crtc)
 	}
 
 	drm_vblank_off(drm, dc->pipe);
+
+	pm_qos_update_request(&dc->qos_request, PM_QOS_DEFAULT_VALUE);
 }
 
 static bool tegra_crtc_mode_fixup(struct drm_crtc *crtc,
@@ -769,6 +771,7 @@ static int tegra_crtc_mode_set(struct drm_crtc *crtc,
 	struct tegra_dc *dc = to_tegra_dc(crtc);
 	struct tegra_dc_window window;
 	u32 value;
+	unsigned long bandwidth;
 	int err;
 
 	drm_vblank_pre_modeset(crtc->dev, dc->pipe);
@@ -809,6 +812,9 @@ static int tegra_crtc_mode_set(struct drm_crtc *crtc,
 	if (err < 0)
 		dev_err(dc->dev, "failed to enable root plane\n");
 
+	bandwidth = mode->clock * window.bits_per_pixel / 8;
+	pm_qos_update_request(&dc->qos_request, bandwidth);
+
 	return 0;
 }
 
@@ -1407,6 +1413,9 @@ static int tegra_dc_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	pm_qos_add_request(&dc->qos_request, PM_QOS_MEMORY_BANDWIDTH,
+			   PM_QOS_DEFAULT_VALUE);
+
 	platform_set_drvdata(pdev, dc);
 
 	return 0;
@@ -1417,6 +1426,8 @@ static int tegra_dc_remove(struct platform_device *pdev)
 	struct tegra_dc *dc = platform_get_drvdata(pdev);
 	int err;
 
+	pm_qos_remove_request(&dc->qos_request);
+
 	err = host1x_client_unregister(&dc->client);
 	if (err < 0) {
 		dev_err(&pdev->dev, "failed to unregister host1x client: %d\n",
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index 6b8fe9d..6029693 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -116,6 +116,8 @@ struct tegra_dc {
 	struct drm_pending_vblank_event *event;
 
 	const struct tegra_dc_soc_info *soc;
+
+	struct pm_qos_request qos_request;
 };
 
 static inline struct tegra_dc *
-- 
1.9.3

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