Messages in this thread |  | | | Subject | Re: sym53c875E-0: PCI clock seems too high | | From | Paul Flinders <> | | Date | 26 Sep 1999 16:06:50 +0100 |
| |
Gerard Roudier <groudier@club-internet.fr> writes:
> The test of the PCI clock is not intended to prevent user from stupidly > breaking their hardware, but some reality test to prevent the driver from > being wrong about its estimation of the SCSI clock of the chip. Applying > the algorithm to the PCI bus and checking the result against the expected > reality (33Mhz), allows to make sure the algorithm is correct. This > algorithm is based on the udelay() stuff of Linux that sometimes may give > weird results, especially on new hardware, and then break the driver > calculation of the SCSI clock.
In which case your chosen 37Mhz seems a very wide tolerance. > > I will NOT remove the reality test of the PCI clock, but allow user to > tell the driver about the reality they choose for the PCI clock frequency. > This will be a boot command option that will be defaulted to 33 MHz. > Probably something like : pciclk=41 to inform the driver about the PCI BUS > being clocked to 41 MHz.
OK - can you also provide some documentation for this in the error message. > > I actually donnot care of people who overclock their hardware. I just ask > them for not wasting our time with problems due to their decision to > overclock. These people must know that hardware that have been overclocked > can be definitely damaged and experience far more error than specs said.
I can certainly understand your frustration with people reporting problems with drivers which subsequently turn out to be because they've overclocked the system. I will not usually report any problem as software unless it persists when I've reset the system to the correct speed. > > Overcloking a CPU that is in fact sold with an underclocked specification > is one thing. Overclocking a BUS and then everything that connect to it by > more than 10% was not imaginable by me. By the way, I think that people > that overclock PCI 33 Mhz buses up to 41MHz or more are just foolish and > plain idiot, but I don't care of them.
You're entitled to your view and I'd agree if I had any expectations of reliability for this machine - but it's my home machine and so I can tolerate more problems than, say, my machine at work or a server. Personally I think that not having ECC memory is more "stupid" if you need reliability.
It's about probability anyway - machines are clocked so fast these days that I don't think you can claim 100% absolute reliability even at the "correct" speed - yes I'm eating into the safety margin but I've hammered this machine fairly hard at 83 MHz FSB (which BTW is still _underclocking_ the memory) without problems so I'm fairly confident that 75Mhz FSB is within reasonably safe limits for the expectations that I have of this hardware.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
|  |