From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Jeffery Date: Thu, 06 Oct 2022 13:38:30 +1030 Subject: [PATCH] ipmi: kcs: Poll OBF briefly to reduce OBE latency In-Reply-To: References: <20220812144741.240315-1-andrew@aj.id.au> <08c20621-e75d-4a72-82e6-b1980304e20a@app.fastmail.com> Message-ID: List-Id: To: linux-aspeed@lists.ozlabs.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Thu, 6 Oct 2022, at 10:24, Corey Minyard wrote: > On Thu, Oct 06, 2022 at 09:42:57AM +1030, Andrew Jeffery wrote: >> Hi Corey, >> >> On Sat, 13 Aug 2022, at 00:17, Andrew Jeffery wrote: >> > The ASPEED KCS devices don't provide a BMC-side interrupt for the host >> > reading the output data register (ODR). The act of the host reading ODR >> > clears the output buffer full (OBF) flag in the status register (STR), >> > informing the BMC it can transmit a subsequent byte. >> > >> > On the BMC side the KCS client must enable the OBE event *and* perform a >> > subsequent read of STR anyway to avoid races - the polling provides a >> > window for the host to read ODR if data was freshly written while >> > minimising BMC-side latency. >> >> Just wondering whether you're happy to pick this one up? I haven't seen >> it hit the IPMI tree yet. > > Sorry. It's in my tree for 6.2 right now. Thanks! > > I can't push it up to for-next until 6.1-rc1 comes out. > No worries, just wanted to make sure it didn't fall through the cracks :) Andrew