Re: HCDP concerns

From: Xavier Bru <>
Date: 2004-09-04 01:44:40
Bjorn Helgaas wrote:

>Let me restate this to see if I understand what you need:
>I think you have ports at 0x3f8 and 0x2f8.  The desired naming
>is 0x3f8 == ttyS0 and 0x2f8 == ttyS1.
>With CONFIG_EFI_PCDP=n, you should get the desired naming, and
>"console=ttyS0" or "console=ttyS1" should both work and go to
>the correct ports (but the output won't start until the serial
>driver initializes).
Yes, but I also want to be able to have the boot traces when system does 
not boot, and also have an
early kdb prompt.

>With CONFIG_EFI_PCDP=y, the first port in the HCDP becomes ttyS0.
>(This is a bug and I'll try to fix it soon.)  "console=ttyS0"
>should work, the output should start early, and it should go to
>the first device in the HCDP.  "console=ttyS1" should also work,
>but the output won't start until later, and it should go to the
>other port (the one that is NOT described first in the HCDP).
yes, but currently our 1rst (and only one) HCDP entry is 2f8, and 
console=ttyS1 gives
also the same serial (2f8). This is why I was looking for the previous 
ttyS0 semantic (3f8).

>I think what you want is a way to
>	(1) get early output, and
>	(2) specify the port where the output should go
>That's perfectly reasonable, but neither scenario above gives
>you that.
>Rather than using the hack of assuming ports at 0x3f8 and 0x2f8,
>I'd like to use this as an excuse to get the cleaner solution
>done.  I'm thinking something like a "console=serial,0x3f8"
>argument to specify the device.  Then we don't have to bind a
>name to the device, so we get rid of the renaming problem.
>And the HCDP/PCDP will become just a default source of the "0x3f8"
>information if it's not on the command line.
>Would that solve the problem?
Yes, it sounds good. In our case we keep our H/PCDP describing where is 
directed the EFI console, that provides the default console for linux, 
and we still have the possibility to override at boot time to go to 
another console.
Thanks a lot for looking in deep to my problem.

>To unsubscribe from this list: send the line "unsubscribe linux-ia64" in
>the body of a message to
>More majordomo info at


 Sincères salutations.
Xavier BRU                 BULL ISD/R&D/INTEL office:     FREC B1-422
tel : +33 (0)4 76 29 77 45          
fax : +33 (0)4 76 29 77 70       
addr: BULL, 1 rue de Provence, BP 208, 38432 Echirolles Cedex, FRANCE

To unsubscribe from this list: send the line "unsubscribe linux-ia64" in
the body of a message to
More majordomo info at
Received on Fri Sep 3 11:50:16 2004

This archive was generated by hypermail 2.1.8 : 2005-08-02 09:20:30 EST