Re: New DRM driver model - gets rid of DRM() macros!

Keith Whitwell
2004-09-29T14:57:42Z

Christoph Hellwig wrote:
> On Wed, Sep 29, 2004 at 03:12:03PM +0100, Keith Whitwell wrote:
>
>>Thinking about it, it may not have been a problem of crashing, but rather that
>> the behaviour visible from a program attempting to read (or poll) was
>>different with noop versions of these functions to NULL versions, and that was
>>causing problems. This is 18 months ago, so yes, I'm being vague.
>>
>>The X server does look at this file descriptor, which is where the problem
>>would have arisen, but only the gamma & maybe ffb drivers do anything with it.
>
>
> Indeed, for read you're returning 0 now instead of the -EINVAL from common
> code when no ->read is present. I'd say the current drm behaviour is a bug,
> but if X drivers rely on it.

I'd agree, but it's a widely distributed bug. I guess we can fix it in the X
server, but even better would be to rip out the code as it's fundamentally
misguided, based on a wierd idea that the kernel would somehow ask the X
server to perform a context switch between two userspace clients...

Keith