Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops

Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]
From: Alan Cox
Date: Friday, December 7, 2007 - 9:04 am

> modern CPU compared to the bus. But the delay really needs to be something

You don't need to. Port 0x80 historically is about 8uS so just udelay(8)
and make sure the initial default delay is conservative enough before the
CPU speed is computed.

0x80 should be fine for anything PC compatible anyway, its specifically
reserved as a debug port and supported for *exactly* that purpose by
many chipsets.

The afflicted laptop should really be taken up with the vendor. If its
got port 0x80 wrong gods knows what else it might have problems with.

Alan
--
Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]

Messages in current thread:
Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern ..., Alan Cox, (Fri Dec 7, 9:04 am)
Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern ..., Dr. David Alan Gilbert, (Sun Dec 9, 6:41 am)
Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern ..., linux-os (Dick Johnson), (Tue Dec 11, 8:41 am)
Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern ..., linux-os (Dick Johnson), (Tue Dec 11, 1:27 pm)
Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern ..., linux-os (Dick Johnson), (Wed Dec 12, 6:11 am)
More info on port 80 symptoms on MCP51 machine., David P. Reed, (Wed Dec 12, 1:07 pm)
Re: More info on port 80 symptoms on MCP51 machine., Rene Herman, (Wed Dec 12, 1:26 pm)
Re: Attitude problems., linux-os (Dick Johnson), (Wed Dec 12, 1:31 pm)
Re: More info on port 80 symptoms on MCP51 machine., David P. Reed, (Wed Dec 12, 1:37 pm)
Re: More info on port 80 symptoms on MCP51 machine., H. Peter Anvin, (Wed Dec 12, 2:05 pm)
Re: Attitude problems., linux-os (Dick Johnson), (Fri Dec 14, 9:01 am)
Re: More info on port 80 symptoms on MCP51 machine., Chuck Ebbert, (Fri Dec 14, 3:05 pm)
Re: More info on port 80 symptoms on MCP51 machine., Rene Herman, (Sat Dec 15, 12:22 am)
RE: More info on port 80 symptoms on MCP51 machine., Allen Martin, (Sat Dec 15, 3:34 pm)
Re: More info on port 80 symptoms on MCP51 machine., H. Peter Anvin, (Sat Dec 15, 3:46 pm)