linux-kernel - Re: [PATCH v3 -next 11/11] serial: 8250_early: Remove setup_early_serial8250

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]

Date:	Fri, 03 Apr 2015 13:38:25 -0400
From:	Peter Hurley <peter@...leysoftware.com>
To:	Yinghai Lu <yinghai@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
CC:	Jiri Slaby <jslaby@...e.cz>, Rob Herring <robh@...nel.org>,
	"linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>
Subject: Re: [PATCH v3 -next 11/11] serial: 8250_early: Remove setup_early_serial8250_console()

On 04/03/2015 12:57 PM, Yinghai Lu wrote:
> On Fri, Apr 3, 2015 at 3:37 AM, Peter Hurley <peter@...leysoftware.com> wrote:
>> On 04/02/2015 10:38 PM, Yinghai Lu wrote:
>>> On Thu, Apr 2, 2015 at 5:22 PM, Yinghai Lu <yinghai@...nel.org> wrote:
>>>
>>>>>>> still have another problem.
>>>>>>> when using console=uart8250,io,0x3f8
>>>>>>> it works as earlycon at first.
>>>>>>> but after handover to normal console
>>>>>>> it will revert back to 9600 again.
>>>>>>
>>>>>> this regression should be caused by:
>>>>>>
>>>>>> commit c7cef0a84912cab3c9df8949b034e4aa62982ec9
>>>>>> Author: Peter Hurley <peter@...leysoftware.com>
>>>>>> Date:   Mon Mar 9 16:27:12 2015 -0400
>>>>>>
>>>>>>     console: Add extensible console matching
>>>>>
>>>> So your whole patchset will need the first patch ?
>>>>
>>>> or can you just drop the first one patch ?
>>>
>>> Please check attached patch that fix regresion by. commit c7cef0a849
>>> ("console: Add extensible console matching")
>>>
>>> or you have better way?
>>
>> Please re-read my first response to this problem.
>>
> 
>> Also, this expectation is an impediment when adding support for other
>> 8250-like designs that don't have the same 8250 divisor registers
>> (ie., _every_ new design). To properly support this requirement for
>> just the existing 8250 hardware will require special probe_baud()
>> functions for: dw_8250, intel byt, intel mid, omap_8250, exar 17v35 series,
>> omap 1510.
> 
> But you can not break old setup!
> 
> old behavior: console=uart8250,io,0x3f8
> 
> when bootloader or firmware has 115200 used already,
> earlycon, and console all keep 115200.
> 
> Now with your change, earlycon will use 115200 still,
> but console will switch to 9600.
> 
>>
>> Is specifying the line speed on the command line really a burden?
>>
> 
> Yes.  We have two setups, and two BIOS versions.
> product version is using 9600 and devel/debug is using 115200.

Wait -- you have earlycon in a product??

> This is a regression, and must be addressed.
> 
> Greg,
> 
> Please don't send merge request for tty-next to Linus before
> this regression get resolved.


--
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/