HCDP concerns

From: Xavier Bru <xavier.bru_at_bull.net>
Date: 2004-09-01 20:25:43
Hello Bjorn and all,

I have some concerns with using kernel 2.6.8.1 (and 2.6.7) with our 
platform that has a new BIOS that provides HCDP.

1) When kernel is configured without h/pcdp support ( CONFIG_EFI_PCDP is 
not set),
the serial console are not initialized (efi.hcdp is not NULL).

A simple fix could be:
--- linux-2.6.8.1-ori/arch/ia64/kernel/setup.c    2004-08-14 
12:54:50.000000000 +0200
+++ linux-2.6.8.1/arch/ia64/kernel/setup.c    2004-08-31 
11:54:02.000000000 +0200
@@ -351,9 +351,9 @@
 #endif
 #ifdef CONFIG_EFI_PCDP
     efi_setup_pcdp_console(*cmdline_p);
+    if (!efi.hcdp)
 #endif
 #ifdef CONFIG_SERIAL_8250_CONSOLE
-    if (!efi.hcdp)
         setup_serial_legacy();
 #endif

2) Our platform has 2 serial ports (let say port 0 at address 3f8, port 
1 at address 2f8). Usually port 0 is seen as ttyS0 & port 1 as ttyS1. 
EFI console redirection is done on port S1 (2f8) & is described through 
HCDP(port 0 is not described).
Using the h/pcdp support ( CONFIG_EFI_PCDP=1), we get some strange 
behaviours:
. "console=ttyS0" boot parameter, as explained in menuconfig takes the 
HCDP table entry as console, but changes the ttyS* order:
ttyS1 for port 0 (3f8) and ttyS0 for port 1 (2f8). Console is OK,  but 
the ttyS0 on port 1 is confusing compared to kernels without hcdp support.
. due to this behaviour, there is no more possibility to have the linux 
console redirection on the port 0 at boot time.
. My understanding was that h/pcdp support should provide some new 
console=efi (or serial)  option to have the console defined by efi used 
by linux as console, but that this should not change the ttyS order, and 
that we should still be able to use console="ttySx" at boot time to have 
the console on port "x".
. specifying no "console=" provides no console as the Conout variable is 
not exported by EFI at runtime. Should it be ?

Thanks in advance for your clarifications.
Xavier
-- 

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

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Received on Wed Sep 1 06:26:54 2004

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