Re: [Dri-devel] bug in light locks?

[Keith W. <ke...@tu...>]

John Dennis wrote:
> I've been trying to track down a DRI client and server deadlock
> problem. I think I now know the problem, I'd appreciate it if others
> could confirm this is a bug or if I have a misunderstanding.
> 
> This is the scenario:
> 
> 1) Client takes heavyweight lock via ioctl, lock now has DRM_LOCK_HELD
> bit or'ed in, high nibble is now 0x8.
> 
> 2) Server requests heavyweight lock on a different context via ioctl,
> lock is held by client, server is suspened pending release of lock by
> client. The DRM_LOCK_CONT flag is or'ed in, high nibble is now 0xC.
> 
> 3) Client wants to take lightweight lock, client currently holds
> lock. 

These locks don't support recursive locking -- if this situation arises, the 
client is broken.

Keith