There is/used to be some code that sets the baud rate to coreboots default on every SMM entry if SMM debug is enabled. Might mess up whatever the OS is doing though, it's not recovering the OS specified values.
On 30.11.2010, at 09:35, "Scott Duplichan" <[email protected]> wrote: > From: [email protected] [mailto:[email protected]] On > Behalf Of Patrick Georgi > Sent: Tuesday, November 30, 2010 11:26 AM > To: [email protected] > Subject: Re: [coreboot] Where does printk(DEBUG, "msg") go after booting? > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Am 30.11.2010 18:16, schrieb Fengwei Zhang: >> I understand the printk(DEBUG, "msg") statement will print out msg on >> the serial port when booting. How about after booting? Where does >> printk(DEBUG, "msg") go after booting? > ]"After booting" the only component that might still be active (and thus > ]able to run our printk) would be SMM. That code shares the same printing > ]routines, so it prints on serial, too. > > One thing to watch for is the OS changing the baud rate. I notice this with > coreboot+seabios and DOS after CtrlAltDel. DOS sets the baud rate to 2400. > The serial output is still present, but the baud rate must be changed to see > it. > > Thanks, > Scott > > > Patrick > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.10 (MingW32) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ > > iEYEARECAAYFAkz1M7IACgkQfp0gE8eLOvQD2ACgyY9lvqgShmNs5i9sbXjoVZEO > rLUAoKOzE7nY7Y0pVH7CE/q03k6lv51w > =Mxeu > -----END PGP SIGNATURE----- > > > > -- > coreboot mailing list: [email protected] > http://www.coreboot.org/mailman/listinfo/coreboot > -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
