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 15:21:53 +0200 [thread overview]
Message-ID: <20190328132153.GZ9224@smile.fi.intel.com> (raw)
In-Reply-To: <20190328130317.GG22720@zn.tnic>
On Thu, Mar 28, 2019 at 02:03:17PM +0100, Borislav Petkov wrote:
> On Tue, Mar 19, 2019 at 09:43:25PM +0300, Andy Shevchenko wrote:
> > If by BIOS or by other means the serial port is configured
> > user might want to skip reconfiguration in the boot code.
>
> That needs more explanation: how can that happen?
I didn't get what is 'that' here? You mean that serial interface becomes
configured before kernel even starts? See below.
> How is the user
> supposed to know whether the serial port is configured in order to use
> this cmdline param?
If the connection to the target is done via serial interface and
firmware and / or bootloader already did necessary configuration.
> Why can't the kernel detect whether the serial port is configured and
> not touch that configuration?
Because it can't at this stage. We simple can't afford to move all serial
drivers (even partially) to the _boot_ part of the kernel.
> A lot of why's and head scratching...
What other why's should be answered?
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2019-03-28 13:21 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 [this message]
2019-03-28 13:42 ` Borislav Petkov
2019-03-28 14:00 ` Andy Shevchenko
2019-03-28 14:13 ` Borislav Petkov
2019-03-28 14:27 ` Andy Shevchenko
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