1a0014c1c6
[ Upstream commit 9891cb54445bc65bf156bda416b6215048c7f617 ]
In case the DRAM is under high load, the MXSFB FIFO might underflow
and that causes visible artifacts. This could be triggered on i.MX8MM
using e.g. "$ memtester 128M" on a device with 1920x1080 panel. The
first "Stuck Address" test of the memtester will completely corrupt
the image on the panel and leave the MXSFB FIFO in odd state.
To avoid this underflow, increase number of outstanding requests to
DRAM from 2 to 16, which is the maximum. This mitigates the issue
and it can no longer be triggered.
Fixes: 45d59d7040 ("drm: Add new driver for MXSFB controller")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Daniel Abrecht <public@danielabrecht.ch>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Stefan Agner <stefan@agner.ch>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210620224759.189351-1-marex@denx.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
59 lines
1.2 KiB
C
59 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2016 Marek Vasut <marex@denx.de>
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*
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* i.MX23/i.MX28/i.MX6SX MXSFB LCD controller driver.
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*/
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#ifndef __MXSFB_DRV_H__
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#define __MXSFB_DRV_H__
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#include <drm/drm_crtc.h>
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#include <drm/drm_device.h>
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#include <drm/drm_encoder.h>
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#include <drm/drm_plane.h>
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struct clk;
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struct mxsfb_devdata {
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unsigned int transfer_count;
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unsigned int cur_buf;
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unsigned int next_buf;
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unsigned int hs_wdth_mask;
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unsigned int hs_wdth_shift;
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bool has_overlay;
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bool has_ctrl2;
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};
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struct mxsfb_drm_private {
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const struct mxsfb_devdata *devdata;
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void __iomem *base; /* registers */
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struct clk *clk;
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struct clk *clk_axi;
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struct clk *clk_disp_axi;
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struct drm_device *drm;
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struct {
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struct drm_plane primary;
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struct drm_plane overlay;
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} planes;
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struct drm_crtc crtc;
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struct drm_encoder encoder;
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struct drm_connector *connector;
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struct drm_bridge *bridge;
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};
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static inline struct mxsfb_drm_private *
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to_mxsfb_drm_private(struct drm_device *drm)
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{
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return drm->dev_private;
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}
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void mxsfb_enable_axi_clk(struct mxsfb_drm_private *mxsfb);
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void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb);
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int mxsfb_kms_init(struct mxsfb_drm_private *mxsfb);
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#endif /* __MXSFB_DRV_H__ */
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