On 11/11/2014 01:37 PM, Paolo Bonzini wrote: > > > On 10/11/2014 21:11, Hannes Reinecke wrote: >> On 11/10/2014 07:32 PM, Paolo Bonzini wrote: >>> On 10/11/2014 16:52, Hannes Reinecke wrote: >>>> After a reset ESP_TCHI should contain the unique ID >>>> of the chip. This value will be overwritten with the >>>> current tranfer count if the transfer count has >>>> previously been set. >>>> So we should always return the chip id if ESP_TCHI >>>> has never been written to. >>> >>> What if ESP_TCHI was written 0? Why should it return the chip id? >>> >> It's a complex thing. The documentation says 'ESP_TCHI returns the chip >> id until been written to'. >> And ESP_TCHI is strictly speaking only valid if the 'Features enabled' >> bit is set in ESP_CFG2. (Not that the driver checks this). >> To handle it correctly we would need to add a flag whenever ESP_TCHI >> is written to, but I thought it'd be slightly too much. > > I'm worried that the chip_id will reappear if you write a low (<65536) > value to ESP_TCLOW/MED/HI. > > Adding the flag is just a couple lines more than this patch, let's do it > right. > Right.
Will be sending an updated patch. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage h...@suse.de +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 21284 (AG Nürnberg)
