[Intel-gfx] [RFC 1/4] x86/platform/intel/iosf_mbi: Add a mutex for punit access

Ville Syrjälä ville.syrjala at linux.intel.com
Fri Jan 13 10:51:27 UTC 2017

On Fri, Jan 13, 2017 at 12:34:54PM +0200, Jarkko Nikula wrote:
> On 01/13/2017 11:26 AM, Ville Syrjälä wrote:
> > It also feels quite hand wavy since the punit could do whatever at
> > any time AFAIK. Eg. if there's some thermal event or something the
> > punit might kick into action. So trying to protect this from the OS
> > side might not be able to avoid these problems entirely. It feels like
> > there really should be some kind of shared hardware/firmware mutex
> > with the punit to arbitrate access to the i2c bus.
> >
> There is an HW semaphore for I2C access. It is implemented in 
> drivers/i2c/busses/i2c-designware-baytrail.c and another set from Hans 
> is adding support for Cherrytrail into it.

Then why do we need anything else?

Ville Syrjälä
Intel OTC

More information about the Intel-gfx mailing list