Messages in this thread | | | Subject | Re: [PATCH] NMI trap revised (was Re: NMI errors in 2.0.30??) | Date | Thu, 8 May 1997 09:27:45 +0200 (MET DST) | From | (Rogier Wolff) |
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Riccardo Facchetti wrote: > > Is this a good idea ? > > On 6 May 1997, Matthias Urlichs wrote: > > > > The best memory checker is a kernel recompile, a network download, and a > > floppy read. At the same time. Repeatedly. I have yet to see a problem that > > didn't eventually show up under this kind of stress.
> + > + /* > + * May be sort out what memory chip is failing ? > + * Heh ... with parity memory we can be a good memory > + * test program too :) > + * It should be something like: > + * > + * (1) disable NMI interrupts writing 1 in bit 7 of > + * port 0x70 > + * (2) reset the NMI memory parity error flag (bit 7) > + * toggling bit 2 of 0x61 port to 1 and then to 0 > + * (3) while all flat memory is tested: > + * (4) write 4Kb page in memory ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > + * (5) test if any NMI is pending: if yes, the > + * last page written is bogus, printk its > + * address. > + * (6) ++ page
I maintain the "sig11" page which explains a lot about bad memory. I allows me to get lots of mails from people with different memory problems. In more than 90% of the cases the problems only show when you do a kernel compile. My memory test program (which is based on the knowledge of a leading expert on semiconductor memory testing.) detects only a very small percentage of memory trouble.
Roger.
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