mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-22 00:20:15 +07:00
ac4eead379
The current dsb API is not really prepared to handle multithread access.
I was debugging an issue that ended up fixed by commit a096883dda
("drm/i915/dsb: Remove PIN_MAPPABLE from the DSB object VMA") and was
puzzled how these atomic operations were guaranteeing atomicity.
if (atomic_add_return(1, &dsb->refcount) != 1)
return dsb;
Thread A could still be initializing dsb struct (and even fail in the
middle) while thread B would take a reference and use it (even
derefencing a NULL cmd_buf).
I don't think the atomic operations here will help much if this were
to support multithreaded scenario in future, so just remove them to
avoid confusion.
v2: Use refcount++ != 0 instead of ++refcount != 1 (from Ville)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191111205024.22853-2-lucas.demarchi@intel.com
Link: https://patchwork.freedesktop.org/patch/msgid/20191116011539.18230-1-lucas.demarchi@intel.com
53 lines
1005 B
C
53 lines
1005 B
C
/* SPDX-License-Identifier: MIT
|
|
*
|
|
* Copyright © 2019 Intel Corporation
|
|
*/
|
|
|
|
#ifndef _INTEL_DSB_H
|
|
#define _INTEL_DSB_H
|
|
|
|
#include <linux/types.h>
|
|
|
|
#include "i915_reg.h"
|
|
|
|
struct intel_crtc;
|
|
struct i915_vma;
|
|
|
|
enum dsb_id {
|
|
INVALID_DSB = -1,
|
|
DSB1,
|
|
DSB2,
|
|
DSB3,
|
|
MAX_DSB_PER_PIPE
|
|
};
|
|
|
|
struct intel_dsb {
|
|
long refcount;
|
|
enum dsb_id id;
|
|
u32 *cmd_buf;
|
|
struct i915_vma *vma;
|
|
|
|
/*
|
|
* free_pos will point the first free entry position
|
|
* and help in calculating tail of command buffer.
|
|
*/
|
|
int free_pos;
|
|
|
|
/*
|
|
* ins_start_offset will help to store start address of the dsb
|
|
* instuction and help in identifying the batch of auto-increment
|
|
* register.
|
|
*/
|
|
u32 ins_start_offset;
|
|
};
|
|
|
|
struct intel_dsb *
|
|
intel_dsb_get(struct intel_crtc *crtc);
|
|
void intel_dsb_put(struct intel_dsb *dsb);
|
|
void intel_dsb_reg_write(struct intel_dsb *dsb, i915_reg_t reg, u32 val);
|
|
void intel_dsb_indexed_reg_write(struct intel_dsb *dsb, i915_reg_t reg,
|
|
u32 val);
|
|
void intel_dsb_commit(struct intel_dsb *dsb);
|
|
|
|
#endif
|