On Sunday 30 September 2007 00:49:05 Benjamin Herrenschmidt wrote:

Well, it's possible that they have a too weak pull-up resistor on those
lines, and thus when asserted to 0, a significant current goes through
causing the whole thing to heat up. That heat added to the residual heat
of a hot boot becomes then enough to trigger the temperature sensor
threshold... just one possible explanation.

Possible, yes.

quoted

That's why I thought about some silicon bug. Why only when it's hot? :)

quoted

Also, the other change I made you do turns these into inputs, thus the

The _EN bits are already all cleared, as you can see in my printk dump.
So clearing them has no effect, of course.
So the ports are Inputs as default on boot.

Hrm, that's weird then, because in that case, changing the output bits
shouldn't have any effect, unless maybe on some chips, the EN bits are
flipped. I don't have anything specific about the rv350 tho.

Can you print which specific DDC register is doing that (it's called
twice right ?) and maybe do a patch preventing that write only for one
of them and let me know if it makes a difference.

Here's the log of a working kernel.
As you can see, I only removed the write for register 0x60 here.
So it only crashes when I clear the bits in this register.
(makes sense, as there's nothing to clear in the other one).

[    0.453703] PCI: Enabling device 0000:00:10.0 (0006 -> 0007)
[    0.649319] radeonfb (0000:00:10.0): Invalid ROM signature 303 should be 0xaa55
[    0.649329] radeonfb: Retrieved PLL infos from Open Firmware
[    0.649340] radeonfb: Reference=27.00 MHz (RefDiv=12) Memory=203.00 Mhz, System=392.00 MHz
[    0.649350] radeonfb: PLL min 12000 max 35000
[    0.650146] DDC REG 0x00000060 IS 0x00000303
[    0.793754] i2c-adapter i2c-2: unable to read EDID block.
[    1.013748] i2c-adapter i2c-2: unable to read EDID block.
[    1.233748] i2c-adapter i2c-2: unable to read EDID block.
[    1.310002] DDC REG 0x0000006C IS 0x00000000
[    1.310007] WRITING
[    1.650506] ieee1394: Host added: ID:BUS[0-00:1023]  GUID[001124fffed98036]
[    1.700986] radeonfb: Monitor 1 type LCD found
[    1.700995] radeonfb: EDID probed
[    1.701001] radeonfb: Monitor 2 type no found
[    1.701015] radeonfb: Using Firmware dividers 0x0002008e from PPLL 0
[    1.701130] radeonfb: Dynamic Clock Power Management enabled
[    1.742608] Console: switching to colour frame buffer device 160x53
[    1.765577] radeonfb: Backlight initialized (radeonbl0)
[    1.765767] radeonfb (0000:00:10.0): ATI Radeon NP 
[    1.776757] Generic RTC Driver v1.07
[    1.777085] Macintosh non-volatile memory driver v1.1
[    1.777429] Linux agpgart interface v0.102
[    1.777739] agpgart: Detected Apple UniNorth 2 chipset

-- 
Greetings Michael.