Re: [tpmdd-devel] [PATCH RFC 0/4] RFC: in-kernel resource manager

[Stefan Berger]

On 01/11/2017 01:03 PM, Jason Gunthorpe wrote:
> On Wed, Jan 11, 2017 at 11:00:43AM +0100, Andreas Fuchs wrote:
>
> > could we please get an ioctl, that switches the "mode" of the fd entirely.
> > I'd like to see the write()/read() support still intact.
> > All my current code uses main-loop based poll on the fd and I don't want
> > to be force to start using threads...
> We currently do not support poll in the kernel for /dev/tpmX.
>
> ie we do not supply a poll method for 'struct file_operations'.
>
> Even worse, the current implementation blocks returning from write()
> until the TPM has completed its work, so it doesn't even make sense to
> combine it with poll.

Newer applications could issue an ioctl() after the open() to unblock 
the write().

    Stefan