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

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Alan Cox wrote:


The vga driver is somewhat misnamed. In console mode we handle everything
back to MDA/HGA and some HGA adapters do need delays.
No they don't. I really, really, really know this for a fact. I wrote ASM drivers for every early video adapter and ran them all through Lotus QA and Software Arts QA. Personally. The only delay needed is caused by not having dual-ported video frame buffers on the original CGA in high res character mode. This caused "snow" when a memory write was done concurrently with the read being done by the scanline character generator. And that delay was done by waiting for a bit in the I/O port space to change. There was NO reason to do waits between I/O instructions. Produce a spec sheet, or even better a machine. I may have an original PC-XT still lying around in the attic, don't know if I can fire it up, but it had such graphics cards. I also have several early high-speed clones that were "overclocked".
I do remind all that 0x80 is a BIOS-specific standard, and is per BIOS - other ports have been used in the history of the IBM PC family by some vendors, and some machines have used it for DMA port mapping!! And 

All do -thats why it is suitable.
Not true. Again, I can produce machines that don't use 0x80. Perhaps that is because I am many years older than you are, and have been writing code for PC compatibles since 1981. (not a typo - this was before the first IBM PC was released to the public).
Windows XP does NOT use it at all. Therefore it may not be supported by 

Older Windows does. Don't know about XP although DOS apps in XP will but
they may virtualise the port.
Show me one line of Windows code written by Microsoft that uses port 80. I don't know what app hackers might have done - there was no protection, and someone might have copied the BIOS for some reason.
I have a simple patch that fixes my primary concern - just change the CMOS_READ and CMOS_WRITE, 64-bit versions of I/O and bootcode vga accesses (first group below) to use the straight inb and outb code. 

Which requires care. Have you verified all the main chipset vendors ?
I obviously have not. Clearly the guys who want this port 80 hack so desperately have not either. That's why we are in this pickle. (well, we only to the extent that I am accepted as having useful input. I'm happy to go if I'm not perceived as being helpful).
I may submit it so that the many others who share my pain will be made 

All .. none of them ?
There is a long standing set of reports of "hwclock" not working on HP dv.000v laptops, where the . stands for 2, 4, 6, and 9. These are all nvidia MCP51 chipset AMD64's.
And if you choose to be such an insulting ****, I may just stop trying to be helpful. I presume that others in the community find my comments helpful. 
I can do some of these off the top of my head


drivers/net/8390.h


Needed for some 8390 devices on ISA bus


drivers/net/de600.c
drivers/net/de600.h


Uses the parallel port which isnt guaranteed to be full ISA speed.


drivers/scsi/ppa.h


Parallel port


drivers/serial/8250.c


Some PC's need delays for certain ops.


drivers/watchdog/wdt_pci.c


That one is a mistake I believe, I'll dig out the docs.



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