kwin/plugins/platforms/drm/gbm_surface.cpp
Martin Flöser 47343fb8f7 [platforms/drm] Use a shared pointer for gbm_surface
Summary:
The gbm_surface is owned by the EglGbmBackend, but it's not the only one
using it. The DrmSurfaceBuffer is also using it and needs it to destroy
the gbm_bo. Now this can become a problem in the following situation:

* a page flip is still pending
* the EglGbmBackend destroys the gbm_surface

-> when the page flip happens the DrmSurfaceBuffer will try to destroy
the gbm_bo and crash as the gbm_surface is no longer valid. This
situation can happen when switching screens or when switching compositing
backend (OpenGL 2 -> OpenGL 3).

To address this problem a class GbmSurface is added which wrapps the
gbm_surface pointer. The EglGbmBackend creates and holds a shared pointer
to the GbmSurface and passes that one to the DrmSurfaceBuffer. So when
cleaning up the gbm_surface only the shared pointer is reset and in case
the DrmSurfaceBuffer still needs it, it can access it without problems.

BUG: 385372
FIXED-IN: 5.11.0

Test Plan: Not yet

Reviewers: #kwin, #plasma, subdiff

Subscribers: plasma-devel, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D8152
2017-10-05 21:32:46 +02:00

55 lines
1.5 KiB
C++

/********************************************************************
KWin - the KDE window manager
This file is part of the KDE project.
Copyright (C) 2017 Martin Flöser <mgraesslin@kde.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#include "gbm_surface.h"
#include <gbm.h>
namespace KWin
{
GbmSurface::GbmSurface(gbm_device *gbm, uint32_t width, uint32_t height, uint32_t format, uint32_t flags)
: m_surface(gbm_surface_create(gbm, width, height, format, flags))
{
}
GbmSurface::~GbmSurface()
{
if (m_surface) {
gbm_surface_destroy(m_surface);
}
}
gbm_bo *GbmSurface::lockFrontBuffer()
{
if (!m_surface) {
return nullptr;
}
return gbm_surface_lock_front_buffer(m_surface);
}
void GbmSurface::releaseBuffer(gbm_bo *bo)
{
if (!bo || !m_surface) {
return;
}
gbm_surface_release_buffer(m_surface, bo);
}
}