[PATCH 2/4] [RFC] [MTD] cfi_probe: remove Intel chip workaround

Alexey Korolev akorolev at infradead.org
Mon Jul 28 10:05:53 EDT 2008


Hi All,

> > For me this workaround breaks detection of a M29W128GL flash because it
> > doesn't switch to CFI Query mode after writing 0xff.
> >
> > This workaround was introduced in 2004 between v2.6.8-rc1 and
> > v2.6.8-rc2 in CVS revision 1.77 of cfi_probe.c.  ("Send 0xFF to switch Intel
> > chips back to read mode too. Some of them ignore 0xF0")
> >
> > Alternatively writing 0xff *before* 0xf0 works with the M29W128GL.
> >
> 
> As far as I know M29W128GL is only chip having troubles with 0xFF.
> Even M29DW128GL works fine with that.
> 
> Writing 0xFF before 0xF0 works fine both M29W128GL, M29DW128GL and
> Intel's flash (we have tried with M18). Not sure though if it would
> work for *all* flash parts.

Several days ago I have asked our specialists about what chips require
0xFF just after 0xF0. Probably it was some early revisions of L30.
Unfortunately the fixup description do not tell us what it was exactly. It was long time ago and it is
not so simple to find out what chips require this. Please stand by for
2-3 days I still believe I could be able to find what it was the chip
exactly. If it was some beta revisions - then it make sence to kill 0xFF
lines. If not it might be necessary to use another fix. 

Thanks,
Alexey




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