From mboxrd@z Thu Jan 1 00:00:00 1970 From: havenyang@126.com (HavenYang) Date: Wed, 5 Aug 2015 08:53:30 +0800 (CST) Subject: what time does host will re-used the prplist memory region. In-Reply-To: <20150804134000.GB13681@linux.intel.com> References: <20150804134000.GB13681@linux.intel.com> Message-ID: <756479b3.d0e.14efb594bf2.Coremail.havenyang@126.com> Dear Matthew Thank you for your feedback, it's very important to me. I suggest your comment for my first question should be wrote to the spec, otherwise, there maybe others confused for this issue and go to the wrong way. At 2015-08-04 21:40:00, "Matthew Wilcox" wrote: >On Tue, Aug 04, 2015@11:29:47AM +0800, HavenYang wrote: >> It says the SQhead indicate Submission Queue entries may be re-used, but it not say the PRPlist related to this command may be re-used or not, I confused. >> >> my question is: >> 1. from host side,?what is the condition can host re-used the prplist memory region for a host command, SQHead or command complete? > >The host can only reuse the PRP list memory when the command has been >completed. The device is entitled to use the PRP list throughout >execution of the command. > >> 2. from device side, what is the condition to update SQHead, fetched command head(simple) or fetched all prp from prplist(complex)? > >The first; the host only takes this as an indication that it can reuse >the SQ entry.