From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: Re: [REGRESSION] "of: Fix premature bootconsole disable with 'stdout-path'" breaks console on tty0 Date: Mon, 16 Mar 2015 19:35:41 +0100 Message-ID: <5507227D.8020408@redhat.com> References: <55070544.9010908@redhat.com> <550717A0.3060603@hurleysoftware.com> <55071D0C.2050700@redhat.com> <55071F87.1050706@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55071F87.1050706@hurleysoftware.com> Sender: stable-owner@vger.kernel.org To: Peter Hurley Cc: Grant Likely , Leif Lindholm , Rob Herring , Greg Kroah-Hartman , stable , devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org Hi, On 16-03-15 19:23, Peter Hurley wrote: > On 03/16/2015 02:12 PM, Hans de Goede wrote: >> Hi, >> >> On 16-03-15 18:49, Peter Hurley wrote: >>> 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. >> >> As said it is an undesirable behavior change, whether you want to call that a regression >> or not is not all that interesting. Fixing it however is important, as e.g. Fedora >> ARM images rely on this behavior, both "regular" arm as well as aarch64. > > What dts file is causing this problem? > Is it in mainline or distributed only in Fedora? This is on allwinner (sunxi) devices such as Allwinner A10 or A20 based boards, currently the setting of stdout-path on these boards is done by (an unmodified) upstream u-boot. To be clear about my aarch64 remark, that relates to the behavior of aarch64 acpi using machines, those will also output to both a serial tty and tty0 when the acpi equivalent of stdout-path is present and points to a serial tty. Regards, Hans