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From: Dmitry Osipenko <digetx@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/3] drm/tegra: dc: Tune up high priority request controls on Tegra20
Date: Fri, 24 May 2019 21:16:25 +0300	[thread overview]
Message-ID: <20190524181627.16490-2-digetx@gmail.com> (raw)
In-Reply-To: <20190524181627.16490-1-digetx@gmail.com>

Tegra20 has a high priority request control that allow to configure
when display's memory client should perform read requests with a higher
priority (Tegra30+ uses other means). Set up the controls for a more
aggressive prefetching to reliably avoid FIFO underflow on a lower memory
frequency, this allow to safely drop the memory bandwidth requirement by
about two times in a most popular cases (only one display active, video
overlay inactive, no scaling is done).

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/gpu/drm/tegra/dc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 079250c85733..3e13948dcdcd 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -1828,12 +1828,12 @@ static void tegra_crtc_atomic_enable(struct drm_crtc *crtc,
 		tegra_dc_writel(dc, value, DC_CMD_INT_POLARITY);
 
 		/* initialize timer */
-		value = CURSOR_THRESHOLD(0) | WINDOW_A_THRESHOLD(0x20) |
-			WINDOW_B_THRESHOLD(0x20) | WINDOW_C_THRESHOLD(0x20);
+		value = CURSOR_THRESHOLD(0) | WINDOW_A_THRESHOLD(0x70) |
+			WINDOW_B_THRESHOLD(0x30) | WINDOW_C_THRESHOLD(0x70);
 		tegra_dc_writel(dc, value, DC_DISP_DISP_MEM_HIGH_PRIORITY);
 
-		value = CURSOR_THRESHOLD(0) | WINDOW_A_THRESHOLD(1) |
-			WINDOW_B_THRESHOLD(1) | WINDOW_C_THRESHOLD(1);
+		value = CURSOR_THRESHOLD(0) | WINDOW_A_THRESHOLD(0) |
+			WINDOW_B_THRESHOLD(0) | WINDOW_C_THRESHOLD(0);
 		tegra_dc_writel(dc, value, DC_DISP_DISP_MEM_HIGH_PRIORITY_TIMER);
 
 		value = VBLANK_INT | WIN_A_UF_INT | WIN_B_UF_INT | WIN_C_UF_INT |
-- 
2.21.0


  reply	other threads:[~2019-05-24 18:17 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-24 18:16 [PATCH v2 0/3] Tegra DRM: Support memory bandwidth management for display Dmitry Osipenko
2019-05-24 18:16 ` Dmitry Osipenko [this message]
2019-05-24 18:16 ` [PATCH v2 2/3] drm/tegra: dc: Extend debug stats with total number of events Dmitry Osipenko
2019-05-24 18:16 ` [PATCH v2 3/3] drm/tegra: Support PM QoS memory bandwidth management Dmitry Osipenko

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