linux-kernel - Re: [PATCH v2 3/7] tty/serial: convert 8250 to generic earlycon

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAL_JsqLccXqcsQXoc1ZLcuqUAQMNHW_iApdNpd1ptnNS+1ut0A@mail.gmail.com>
Date:	Tue, 10 Jun 2014 17:38:22 -0500
From:	Rob Herring <robherring2@...il.com>
To:	Tony Luck <tony.luck@...il.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Yinghai Lu <yinghai@...nel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>,
	Jiri Slaby <jslaby@...e.cz>,
	Catalin Marinas <catalin.marinas@....com>,
	Russell King <linux@....linux.org.uk>,
	Will Deacon <will.deacon@....com>,
	Arnd Bergmann <arnd@...db.de>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2 3/7] tty/serial: convert 8250 to generic earlycon

On Tue, Jun 10, 2014 at 3:52 PM, Tony Luck <tony.luck@...il.com> wrote:
> On Mon, Jun 9, 2014 at 4:18 PM, Rob Herring <robherring2@...il.com> wrote:
>> It should do auto detect of the baud-rate if it is not specified which
>> for 8250 is just reading the baud-rate divider and calculating the
>> baud-rate using the uart clock. It should just reprogram the divider
>> with the same divider value. I don't see anything obvious why this
>> would have broken.
>
> Something very weird is happening.  Output is good so long as I put the
> trailing ",115200" on the command line.
>
> But I made early_serial8250_setup() printk() the return value it got
> from probe_baud() - in case is was somehow getting 115201 or some
> other silly value ... nope. Exactly 115200.
>
> I also can't explain why the "noise" comes and goes a dozen
> times during boot,
>
> Does some other place in the kernel look at the "uart..." command
> line argument?

Would you be using drivers/firmware/pcdp.c as that is ia64 only? That
shouldn't have an impact that I can see.

Can you print the options string in serial8250_console_setup? Maybe it
is getting lost when the real console is setup.

Rob
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/