Hi Hans, On 03/16/2015 12:31 PM, Hans de Goede wrote: > Hi All, > > While updating my local working tree to 4.0-rc4 this morning I noticed that I no longer > get console / kernel messages output on the hdmi output of my ARM board / on tty0 > > This is caused by: > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/of?id=2fa645cb2703d9b3786d850db815414dfeefa51d > > Reverting this commit fixes this for me. > > What is happening here is that the "add_preferred_console("stdout-path", 0, NULL);" > happens before the tty0 registers stopping tty0 from becoming part of the console list > since there already is a preferred console at that time. > > This is an undesirable behavior change caused by the commit in question, on boards > where there is both video output, and a serial console configured through stdout-path > we want to have console output on both as we do not know which of the 2 will actually > be hooked up by the user. I don't see this as a regression, but rather a misconfiguration. 1. Your DT indicates the stdout device is a serial console; that is the expected outcome. Here's what ePAPR has to say on the chosen/stdout-path property node: "A string that specifies the full path to the node representing the device to be used for boot console output. If the character ":" is present in the value it terminates the path. The value may be an alias." If the serial console is not the stdout device then the DT should not claim it is. 2. The tty0 console is not now, and has never been, always enabled. The tty0 console is only enabled when either, a) there is no other console b) when specified on the command line (ie., "console=tty0") or by prom/dt. Your situation is akin to adding the serial console to the command line; if "console=tty0" is not also explicitly added, there is no boot console output to tty0. 3. This same breakage will happen if any other device registers a console matching the stdout-path at console_init() time (ie, with console_initcall() macro) before the dummy console. The order in which consoles are inited via console_initcall() is dependent on link order, so essentially not controllable across different subsystems (or if there were consoles defined with the arch itself). That said, I'll look into fixing your use-case automagically without requiring configuration changes. Regards, Peter Hurley -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
