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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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fc8fd40eb2
So I just wanted to add a new field to struct drm_device and accidentally stumbled over something. According to comments dev->open_count is protected by dev->count_lock, but that's totally not the case. It's protected by drm_global_mutex. Unfortunately the vga switcheroo callbacks took this comment at face value. The problem is that we can't just take the drm_global_mutex because: - It would lead to a locking inversion with the driver load/unload paths. - It wouldn't actually protect anything, for that we'd need to wrap the entire vga switcheroo code in the drm_global_mutex. And I'm not sure whether that would actually solve anything. What we probably want is a try_to_grab_switcheroo reference kind of thing which is used in the driver's ->open callback. Then we could move all that ->can_switch madness into the vga switcheroo core where it really belongs. But since that would amount to real work take the easy way out and just add a comment. It's definitely not going to make anything worse since doing switcheroo state changes while restarting X just isn't recommended. Even though the delayed switching code does exactly that. v2: - Simplify the ->can_switch implementations more (Thierry) - Fix comment about the dev->open_count locking (Thierry) Cc: Thierry Reding <treding@nvidia.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> (v1) Reviewed-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> |
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| .. | ||
| core | ||
| dispnv04 | ||
| Kconfig | ||
| Makefile | ||
| nouveau_abi16.c | ||
| nouveau_abi16.h | ||
| nouveau_acpi.c | ||
| nouveau_acpi.h | ||
| nouveau_agp.c | ||
| nouveau_agp.h | ||
| nouveau_backlight.c | ||
| nouveau_bios.c | ||
| nouveau_bios.h | ||
| nouveau_bo.c | ||
| nouveau_bo.h | ||
| nouveau_chan.c | ||
| nouveau_chan.h | ||
| nouveau_connector.c | ||
| nouveau_connector.h | ||
| nouveau_crtc.h | ||
| nouveau_debugfs.c | ||
| nouveau_debugfs.h | ||
| nouveau_display.c | ||
| nouveau_display.h | ||
| nouveau_dma.c | ||
| nouveau_dma.h | ||
| nouveau_dp.c | ||
| nouveau_drm.c | ||
| nouveau_drm.h | ||
| nouveau_encoder.h | ||
| nouveau_fbcon.c | ||
| nouveau_fbcon.h | ||
| nouveau_fence.c | ||
| nouveau_fence.h | ||
| nouveau_gem.c | ||
| nouveau_gem.h | ||
| nouveau_hwmon.c | ||
| nouveau_hwmon.h | ||
| nouveau_ioc32.c | ||
| nouveau_ioctl.h | ||
| nouveau_prime.c | ||
| nouveau_reg.h | ||
| nouveau_sgdma.c | ||
| nouveau_sysfs.c | ||
| nouveau_sysfs.h | ||
| nouveau_ttm.c | ||
| nouveau_ttm.h | ||
| nouveau_vga.c | ||
| nouveau_vga.h | ||
| nv04_fbcon.c | ||
| nv04_fence.c | ||
| nv10_fence.c | ||
| nv10_fence.h | ||
| nv17_fence.c | ||
| nv50_display.c | ||
| nv50_display.h | ||
| nv50_fbcon.c | ||
| nv50_fence.c | ||
| nv84_fence.c | ||
| nvc0_fbcon.c | ||
| nvc0_fence.c | ||