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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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5ee5a81df5
The plane allocator has been inherently racy since the beginning of the transition to atomic updates, as the allocator lock is released between free plane check (at .atomic_check() time) and the reservation (at .atomic_update() time). To fix it, create a new allocator solely based on the atomic plane states without keeping any external state and perform allocation in the .atomic_check() handler. The core idea is to replace the free planes bitmask with a collective knowledge based on the allocated hardware plane(s) for each KMS plane. The allocator then loops over all plane states to compute the free planes bitmask, allocates hardware planes based on that bitmask, and stores the result back in the plane states. For this to work we need to access the current state of planes not touched by the atomic update. To ensure that it won't be modified, we need to lock all planes using drm_atomic_get_plane_state(). This effectively serializes atomic updates from .atomic_check() up to completion, either when swapping the states if the check step has succeeded, or when freeing the states if the check step has failed. Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
56 lines
1.6 KiB
C
56 lines
1.6 KiB
C
/*
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* rcar_du_group.c -- R-Car Display Unit Planes and CRTCs Group
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*
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* Copyright (C) 2013-2014 Renesas Electronics Corporation
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*
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* Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#ifndef __RCAR_DU_GROUP_H__
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#define __RCAR_DU_GROUP_H__
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#include <linux/mutex.h>
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#include "rcar_du_plane.h"
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struct rcar_du_device;
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/*
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* struct rcar_du_group - CRTCs and planes group
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* @dev: the DU device
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* @mmio_offset: registers offset in the device memory map
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* @index: group index
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* @use_count: number of users of the group (rcar_du_group_(get|put))
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* @used_crtcs: number of CRTCs currently in use
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* @lock: protects the DPTSR register
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* @planes: planes handled by the group
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*/
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struct rcar_du_group {
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struct rcar_du_device *dev;
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unsigned int mmio_offset;
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unsigned int index;
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unsigned int use_count;
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unsigned int used_crtcs;
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struct mutex lock;
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struct rcar_du_planes planes;
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};
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u32 rcar_du_group_read(struct rcar_du_group *rgrp, u32 reg);
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void rcar_du_group_write(struct rcar_du_group *rgrp, u32 reg, u32 data);
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int rcar_du_group_get(struct rcar_du_group *rgrp);
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void rcar_du_group_put(struct rcar_du_group *rgrp);
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void rcar_du_group_start_stop(struct rcar_du_group *rgrp, bool start);
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void rcar_du_group_restart(struct rcar_du_group *rgrp);
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int rcar_du_group_set_routing(struct rcar_du_group *rgrp);
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#endif /* __RCAR_DU_GROUP_H__ */
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