099d1c290e
Lets not trick ourselves into thinking "drm_device" objects are not ref-counted. That's just utterly stupid. We manage "drm_minor" objects on each drm-device and each minor can have an unlimited number of open handles. Each of these handles has the drm_minor (and thus the drm_device) as private-data in the file-handle. Therefore, we may not destroy "drm_device" until all these handles are closed. It is *not* possible to reset all these pointers atomically and restrict access to them, and this is *not* how this is done! Instead, we use ref-counts to make sure the object is valid and not freed. Note that we currently use "dev->open_count" for that, which is *exactly* the same as a reference-count, just open coded. So this patch doesn't change any semantics on DRM devices (well, this patch just introduces the ref-count, anyway. Follow-up patches will replace open_count by it). Also note that generic VFS revoke support could allow us to drop this ref-count again. We could then just synchronously disable any fops->xy() calls. However, this is not the case, yet, and no such patches are in sight (and I seriously question the idea of dropping the ref-cnt again). Signed-off-by: David Herrmann <dh.herrmann@gmail.com> |
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.. | ||
armada | ||
ast | ||
bochs | ||
cirrus | ||
exynos | ||
gma500 | ||
i2c | ||
i810 | ||
i915 | ||
mga | ||
mgag200 | ||
msm | ||
nouveau | ||
omapdrm | ||
panel | ||
qxl | ||
r128 | ||
radeon | ||
rcar-du | ||
savage | ||
shmobile | ||
sis | ||
tdfx | ||
tegra | ||
tilcdc | ||
ttm | ||
udl | ||
via | ||
vmwgfx | ||
ati_pcigart.c | ||
drm_agpsupport.c | ||
drm_auth.c | ||
drm_buffer.c | ||
drm_bufs.c | ||
drm_cache.c | ||
drm_context.c | ||
drm_crtc.c | ||
drm_crtc_helper.c | ||
drm_debugfs.c | ||
drm_dma.c | ||
drm_dp_helper.c | ||
drm_drv.c | ||
drm_edid.c | ||
drm_edid_load.c | ||
drm_encoder_slave.c | ||
drm_fb_cma_helper.c | ||
drm_fb_helper.c | ||
drm_flip_work.c | ||
drm_fops.c | ||
drm_gem.c | ||
drm_gem_cma_helper.c | ||
drm_global.c | ||
drm_hashtab.c | ||
drm_info.c | ||
drm_ioc32.c | ||
drm_ioctl.c | ||
drm_irq.c | ||
drm_lock.c | ||
drm_memory.c | ||
drm_mipi_dsi.c | ||
drm_mm.c | ||
drm_modes.c | ||
drm_panel.c | ||
drm_pci.c | ||
drm_platform.c | ||
drm_prime.c | ||
drm_rect.c | ||
drm_scatter.c | ||
drm_stub.c | ||
drm_sysfs.c | ||
drm_trace.h | ||
drm_trace_points.c | ||
drm_usb.c | ||
drm_vm.c | ||
drm_vma_manager.c | ||
Kconfig | ||
Makefile | ||
README.drm |
************************************************************ * For the very latest on DRI development, please see: * * http://dri.freedesktop.org/ * ************************************************************ The Direct Rendering Manager (drm) is a device-independent kernel-level device driver that provides support for the XFree86 Direct Rendering Infrastructure (DRI). The DRM supports the Direct Rendering Infrastructure (DRI) in four major ways: 1. The DRM provides synchronized access to the graphics hardware via the use of an optimized two-tiered lock. 2. The DRM enforces the DRI security policy for access to the graphics hardware by only allowing authenticated X11 clients access to restricted regions of memory. 3. The DRM provides a generic DMA engine, complete with multiple queues and the ability to detect the need for an OpenGL context switch. 4. The DRM is extensible via the use of small device-specific modules that rely extensively on the API exported by the DRM module. Documentation on the DRI is available from: http://dri.freedesktop.org/wiki/Documentation http://sourceforge.net/project/showfiles.php?group_id=387 http://dri.sourceforge.net/doc/ For specific information about kernel-level support, see: The Direct Rendering Manager, Kernel Support for the Direct Rendering Infrastructure http://dri.sourceforge.net/doc/drm_low_level.html Hardware Locking for the Direct Rendering Infrastructure http://dri.sourceforge.net/doc/hardware_locking_low_level.html A Security Analysis of the Direct Rendering Infrastructure http://dri.sourceforge.net/doc/security_low_level.html