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From: "Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>
To: The development of GNU GRUB <grub-devel@gnu.org>
Cc: Iain Barker <IBarker@acmepacket.com>,
	Seth Goldberg <seth.goldberg@oracle.com>
Subject: Re: HP root-caues analysis for GRUB "Red screen of death" on	DL120/DL360 G7 servers
Date: Thu, 08 Dec 2011 21:42:24 +0100	[thread overview]
Message-ID: <4EE12130.5080001@gmail.com> (raw)
In-Reply-To: <alpine.GSO.2.00.1112081223150.11118@oretfbsg>

On 08.12.2011 21:23, Seth Goldberg wrote:
>
>  Is this Legacy GRUB they're talking about maybe?
Can be. Then they use unsupported software to begin with.
>
>
>  --S
>
> Quoting Vladimir 'φ-coder/phcoder' Serbinenko, who wrote the following 
> on...:
>
>>
>>> 1) Grub installs its own INT13 handler
>>> 2) Near the end of the chain loading process, Grub loads an image of 
>>> the 
>> Linux kernel into memory which wipes out their Int13 handler.
>>> 3) Right before grub transfers control to the kernel to boot, grub 
>>> makes a 
>> call to a function to turn off the floppy drive.
>>> 4) The call to the floppy code then makes an Int13 call to the handler 
>> which has been overwritten by the kernel and thereby results in the 
>> red screen.
>>>
>> This text seems to be contradictory. INT13 handler is installed if 
>> drivemap is useful only with chainload. But then it mentions Linux 
>> loading. Also the call to stop floppy doesn't call BIOS:
>> static inline void
>> grub_stop_floppy (void)
>> {
>>   grub_outb (0, GRUB_FLOPPY_REG_DIGITAL_OUTPUT);
>> }
>> May I see the configfile in question?
>> Also GRUB does calculate the safe place based on memory layout, 
>> looking at code I see the problem that it's calculated before 
>> installing drivemap hook. While this should be fixed, I see no reason 
>> to use drivemap with Linux.
>>> _end quoted text_
>>>
>>> Regards,
>>> Iain Barker - Platform Engineering, Acme Packet.
>>> [yoshac@member.fsf.org]
>>>
>>>
>>> _______________________________________________
>>> Grub-devel mailing list
>>> Grub-devel@gnu.org
>>> https://lists.gnu.org/mailman/listinfo/grub-devel
>>>
>>
>>
>> -- 
>> Regards
>> Vladimir 'φ-coder/phcoder' Serbinenko
>>
>>
>> _______________________________________________
>> Grub-devel mailing list
>> Grub-devel@gnu.org
>> https://lists.gnu.org/mailman/listinfo/grub-devel
>>
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko



  reply	other threads:[~2011-12-08 20:42 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-08 19:39 HP root-caues analysis for GRUB "Red screen of death" on DL120/DL360 G7 servers Iain Barker
2011-12-08 20:16 ` Vladimir 'φ-coder/phcoder' Serbinenko
2011-12-08 20:23   ` Seth Goldberg
2011-12-08 20:42     ` Vladimir 'φ-coder/phcoder' Serbinenko [this message]
  -- strict thread matches above, loose matches on Subject: below --
2011-12-08 15:36 Iain Barker

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