From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cyril Hrubis Date: Thu, 2 Apr 2020 11:31:27 +0200 Subject: [LTP] [PATCH 2/2] device_drivers/uart01: Add uart01 test In-Reply-To: References: <20200327134707.4532-1-chrubis@suse.cz> <20200327134707.4532-3-chrubis@suse.cz> <20200330152122.GA2699@yuki.lan> <20200331180816.GE2900@yuki.lan> <20200401131220.GA3627@yuki.lan> Message-ID: <20200402093127.GA28452@yuki.lan> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it Hi! > >Indeed but it does not make sense tu run it with a different baud rates, > >since the data are not transmitted at all. > The data exchanged between Tx|Rx and buffer have nothing to do with > baudrate? > I think the baudrate is control Tx|Rx send and receive date rate to|from > buffer. That's what I'm not sure about, the documentation says that in loopback mode data written to the port immediatelly appears on the receiving end, which would mean that the uart speed does not matter at all. Can you try a quick test? If you measure the time the test spends writing data in loopback mode for a different uart speeds and they do not differ the uart speed does not matter. > >Unfortunately it does not seem to work on my AMD based desktop at all, > >my guess is that the loopback bit is silently ignored by the hardware. > >Which means that we cannot enable the test by default in loopback mode > >after all > I will test on my laptop and feedback result today, if it does no work , we > should check the uart driver what different between x86 and arm64. I bet that this differs chipset by chipset and I do not think there is anything wrong with the uart driver per se. -- Cyril Hrubis chrubis@suse.cz