From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 7/7] x86/boot: Support nocfg parameter for earlyprintk
Date: Thu, 28 Mar 2019 16:00:39 +0200 [thread overview]
Message-ID: <20190328140039.GC9224@smile.fi.intel.com> (raw)
In-Reply-To: <20190328134213.GJ22720@zn.tnic>
On Thu, Mar 28, 2019 at 02:42:13PM +0100, Borislav Petkov wrote:
> On Thu, Mar 28, 2019 at 03:21:53PM +0200, Andy Shevchenko wrote:
> > If the connection to the target is done via serial interface and
> > firmware and / or bootloader already did necessary configuration.
>
> Again: how is the user supposed to know that?
How one knows that she is typing on keyboard right now and not on touch screen?
I really don't get this. User either knows this beforehand or doesn't care.
Maybe she needs to read documentation on hardware at some point?
> When a user sees "nocfg"'s
> documentation, how is the user supposed to decide whether she needs
> to supply nocfg or not?
The problem nocfg tries to solve is a hard coded default baud rate and
impossibility to know at this stage all parameters of the serial interface.
> Which exact setups will need to supply nocfg on the cmdline?
If it's _non-standard_ serial interface (by meaning of I/O accessors and port
addresses), user may consider to use this options in case the interface to
communicate with kernel is serial one and its configuration is done by other
means (firmware / bootloader / EFI / etc).
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2019-03-28 14:00 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-19 18:43 [PATCH v2 0/7] x86/boot: Enable earlyprintk for HS UARTs Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 1/7] x86/boot: Convert early_serial_base to unsigned long Andy Shevchenko
2019-03-28 8:28 ` Borislav Petkov
2019-03-28 9:09 ` Andy Shevchenko
2019-03-28 10:54 ` Borislav Petkov
2019-03-19 18:43 ` [PATCH v2 2/7] x86/boot: Introduce helpers for serial I/O Andy Shevchenko
2019-03-28 12:32 ` Borislav Petkov
2019-03-28 13:11 ` Andy Shevchenko
2019-03-28 13:28 ` Borislav Petkov
2019-03-28 13:52 ` Andy Shevchenko
2019-03-28 14:05 ` Borislav Petkov
2019-03-28 14:20 ` Andy Shevchenko
2019-03-28 14:34 ` Borislav Petkov
2019-03-28 14:51 ` Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 3/7] x86/boot: Split out parse_serial_port() helper for earlyprintk Andy Shevchenko
2019-03-28 12:35 ` Borislav Petkov
2019-03-28 13:15 ` Andy Shevchenko
2019-03-28 13:39 ` Borislav Petkov
2019-03-28 13:50 ` Andy Shevchenko
2019-03-28 14:03 ` Borislav Petkov
2019-03-28 14:23 ` Andy Shevchenko
2019-03-28 14:35 ` Borislav Petkov
2019-03-28 14:49 ` Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 4/7] x86/boot: Allow longer parameter list " Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 5/7] x86/boot: Add MMIO byte accessors Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 6/7] x86/boot: Introduce MMIO accessors and their support in earlyprintk Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 7/7] x86/boot: Support nocfg parameter for earlyprintk Andy Shevchenko
2019-03-20 15:05 ` Randy Dunlap
2019-03-20 15:17 ` Andy Shevchenko
2019-03-20 15:19 ` Randy Dunlap
2019-03-20 16:15 ` Andy Shevchenko
2019-03-20 16:30 ` Borislav Petkov
2019-03-20 17:29 ` Andy Shevchenko
2019-03-28 13:03 ` Borislav Petkov
2019-03-28 13:21 ` Andy Shevchenko
2019-03-28 13:42 ` Borislav Petkov
2019-03-28 14:00 ` Andy Shevchenko [this message]
2019-03-28 14:13 ` Borislav Petkov
2019-03-28 14:27 ` Andy Shevchenko
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