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Re: More "issues" with -current - i2c problems

On Sat, 12 Oct 2013, Paul Goyette wrote:

I recently updated some of my machines from 6.99.23 (late July 2013) to 6.99.24 (mid October). After having fought and won a battle with the boot-loader, I'm now seeing some new problems, with i2c/piixpm.

8< snip >8

I suspect that this behavior was introduced when i2c was modified (by soren?) to permit configurations that don't have hardwired i2c addresses. Both sdtemp and spdmem modules have hardwired addresses only, yet it would seem that the bus is being scanned and devices are being "probed" at addresses other than those that are explicitly referenced in these modules/drivers. (And one of these devices apparently has access to the BIOS's EPROM settings!)

I tried to back out the changes to i2c, but still saw the same problem.

But then I noticed that Soren had also modified the piixpm(4) driver to attach multiple iic* on SB800 hardware. Some investigation shows that accessing iic[123] using i2cscan(8) causes all sorts of problems, and actually locks up the i2c bus on iic0!

So I rebuilt another test kernel without the piixpm changes and sure enough, everything seems to work correctly now. Only iic0 is found, and the modules can load successfully.

Finally, with all sources brought backup to date, and having changed my kernel config file to define only one

        iic0 at i2cbus0

things are back to normal.

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