From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Jeffery Date: Thu, 06 Oct 2022 09:42:57 +1030 Subject: [PATCH] ipmi: kcs: Poll OBF briefly to reduce OBE latency In-Reply-To: <20220812144741.240315-1-andrew@aj.id.au> References: <20220812144741.240315-1-andrew@aj.id.au> Message-ID: <08c20621-e75d-4a72-82e6-b1980304e20a@app.fastmail.com> List-Id: To: linux-aspeed@lists.ozlabs.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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. Cheers, Andrew