kwin/plugins/platforms/drm/drm_buffer_gbm.h
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the gbm_bo and crash as the gbm_surface is no longer valid.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

63 lines
1.6 KiB
C++

/********************************************************************
KWin - the KDE window manager
This file is part of the KDE project.
Copyright 2017 Roman Gilg <subdiff@gmail.com>
Copyright 2015 Martin Gräßlin <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/>.
*********************************************************************/
#ifndef KWIN_DRM_BUFFER_GBM_H
#define KWIN_DRM_BUFFER_GBM_H
#include "drm_buffer.h"
#include <memory>
struct gbm_bo;
namespace KWin
{
class DrmBackend;
class GbmSurface;
class DrmSurfaceBuffer : public DrmBuffer
{
public:
DrmSurfaceBuffer(DrmBackend *backend, const std::shared_ptr<GbmSurface> &surface);
~DrmSurfaceBuffer();
bool needsModeChange(DrmBuffer *b) const override {
if (DrmSurfaceBuffer *sb = dynamic_cast<DrmSurfaceBuffer*>(b)) {
return hasBo() != sb->hasBo();
} else {
return true;
}
}
bool hasBo() const {
return m_bo != nullptr;
}
void releaseGbm() override;
private:
std::shared_ptr<GbmSurface> m_surface;
gbm_bo *m_bo = nullptr;
};
}
#endif