linux-dev/drivers/char/drm/drm_lock.c, branch master

drm: reorganise drm tree to be more future proof.

2008-07-14T00:45:01Z

With the coming of kernel based modesetting and the memory manager stuff, the everything in one directory approach was getting very ugly and starting to be unmanageable. This restructures the drm along the lines of other kernel components. It creates a drivers/gpu/drm directory and moves the hw drivers into subdirectores. It moves the includes into an include/drm, and sets up the unifdef for the userspace headers we should be exporting. Signed-off-by: Dave Airlie

drm: disable tasklets not IRQs when taking the drm lock spinlock

2008-05-07T02:22:39Z

Signed-off-by: Dave Airlie

drm: Fix race that can lockup the kernel

2008-03-16T23:54:58Z

The i915_vblank_swap() function schedules an automatic buffer swap upon receipt of the vertical sync interrupt. Such an operation is lengthy so it can't be allowed to happen in normal interrupt context, thus the DRM implements this by scheduling the work in a kernel softirq-scheduled tasklet. In order for the buffer swap to work safely, the DRM's central lock must be taken, via a call to drm_lock_take() located in drivers/char/drm/drm_irq.c within the function drm_locked_tasklet_func(). The lock-taking logic uses a non-interrupt-blocking spinlock to implement the manipulations needed to take the lock. This semantic would be safe if all attempts to use the spinlock only happen from process context. However this buffer swap happens from softirq context which is really a form of interrupt context. Thus we have an unsafe situation, in that drm_locked_tasklet_func() can block on a spinlock already taken by a thread in process context which will never get scheduled again because of the blocked softirq tasklet. This wedges the kernel hard. To trigger this bug, run a dual-head cloned mode configuration which uses the i915 drm, then execute an opengl application which synchronizes buffer swaps against the vertical sync interrupt. In my testing, a lockup always results after running anywhere from 5 minutes to an hour and a half. I believe dual-head is needed to really trigger the problem because then the vertical sync interrupt handling is no longer predictable (due to being interrupt-sourced from two different heads running at different speeds). This raises the probability of the tasklet trying to run while the userspace DRI is doing things to the GPU (and manipulating the DRM lock). The fix is to change the relevant spinlock semantics to be the interrupt-blocking form. After this change I am no longer able to trigger the lockup; the longest test run so far was 20 hours (test stopped after that point). Note: I have examined the places where this spinlock is being employed; all are reasonably short bounded sequences and should be suitable for interrupts being blocked without impacting overall kernel interrupt response latency. Signed-off-by: Mike Isely Signed-off-by: Dave Airlie

Use helpers to obtain task pid in printks

2007-10-19T18:53:43Z

The task_struct->pid member is going to be deprecated, so start using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in the kernel. The first thing to start with is the pid, printed to dmesg - in this case we may safely use task_pid_nr(). Besides, printks produce more (much more) than a half of all the explicit pid usage. [akpm@linux-foundation.org: git-drm went and changed lots of stuff] Signed-off-by: Pavel Emelyanov Cc: Dave Airlie Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

drm: Replace DRM_IOCTL_ARGS with (dev, data, file_priv) and remove DRM_DEVICE.

2007-10-15T00:38:20Z

The data is now in kernel space, copied in/out as appropriate according to t This results in DRM_COPY_{TO,FROM}_USER going away, and error paths to deal with those failures. This also means that XFree86 4.2.0 support for i810 DR is lost. Signed-off-by: Dave Airlie

drm: Replace filp in ioctl arguments with drm_file *file_priv.

2007-10-15T00:38:20Z

As a fallout, replace filp storage with file_priv storage for "unique identifier of a client" all over the DRM. There is a 1:1 mapping, so this should be a noop. This could be a minor performance improvement, as everyth on Linux dereferenced filp to get file_priv anyway, while only the mmap ioct went the other direction. Signed-off-by: Dave Airlie

drm: Remove DRM_ERR OS macro.

2007-10-15T00:38:19Z

This was used to make all ioctl handlers return -errno on linux and errno on *BSD. Instead, just return -errno in shared code, and flip sign on return f shared code to *BSD code. Signed-off-by: Dave Airlie

drm: detypedeffing continues...

2007-07-11T06:53:40Z

Signed-off-by: Dave Airlie

drm: remove drm_file_t, drm_device_t and drm_head_t typedefs

2007-07-11T05:53:27Z

some drivers still todo. Signed-off-by: Dave Airlie

drm: remove a bunch of typedefs on the userspace interface

2007-07-11T05:27:12Z

This moves a bunch of typedefs into a !defined __KERNEL__ to keep userspace API compatiblity, it changes all internal usages to structs/enum/unions. Signed-off-by: Dave Airlie