On Thu, 4 Oct 2012 18:30:11 +0200, Jean Delvare wrote: > Hi Andrew, > > On Thu, 4 Oct 2012 11:30:45 -0400, Andrew Potter wrote: > > Hi, I wasn't quite sure from the information on lm-sensors.org how to open > > an official ticket, but the details of my problem are here: > > > > https://bbs.archlinux.org/viewtopic.php?pid=1170583 > > > > Basically, when I probe i915 gmbus panel (i2c-2) with sensors-detect, when > > it probes address 0x4f my monitor settings (I think the sharpness mostly) > > are changed drastically. This is persistent over any operating system and > > reboot, leading me to believe a) its a hardware issue, or b) nothing > > usually touches whatever values were changed. Any help would be greatly > > appreciated, in the forum post I've also included some experimentation with > > i2c-tools. The problem originally occured on an Arch Linux system. Let me > > know if you need anything else! > > Thanks for reporting. We have had that kind of problem popping up every > other year or so, and take such reports very seriously. We've done our > best to make sensors-detect as safe as possible, but the fact is, the > I2C and SMBus protocols do not support device probing in general, so > the whole thing is a hack, and hacks can turn bad sometimes. > > Please keep in mind that everything you will do to investigate and > solve this issue (including things I or others may suggest you do) may > make things even worse than they are today. So it's all up to you what > you want to do and when you prefer to stop and stick with what you have. > > First thing I would like to know is the version of lm-sensors (or > sensors-detect) you have been running. > > Second thing I would like to know is the exact revision of your laptop > HP Pavillon DV7. If possible, provide the dmidecode output. We want to > document the problem and prevent it from happening to other users with > the same hardware, using a blacklist if needed. > > One thing I don't quite understand is how there can be two different > graphics chips (one Intel, one Nvidia) in a laptop. What sense does it > make, and which one are you using? If the Intel is an integrated thing > and the Nvidia chip was added and is supposed to be better, then I > would suppose that's what you're using, but then I do not understand > how messing up with the Intel I2C buses can have any adverse effect. > > It might be a good idea to prevent scanning of I2C buses on graphics > cards by default, as we do for multimedia (TV) cards already. These > days drm drivers should take care of instantiating the hardware > monitoring devices present without user-space probing, so it's probably > doing more harm than good. > > You said you ran i2cdump on the chip, did you save the output? I'd like > to take a look. > > The only chance to get your system back to its original state by > software is to know what chips exactly are on the I2C bus of your Intel > graphics chip and in particular at I2C address 0x4a. Unfortunately this > information is usually very hard to get. > > Another thing you should try is: > * Power down the machine. > * Remove the battery, unplug the AC adapter. > * Wait 1 minute at least, 10 minutes if you have time. > * Put the battery and AC adapter back in place. > * Power up the machine again. > > With some luck this will restore the original state. It has worked for > others in the past. Andrew, were you able to solve the problem somehow, using my suggestion or otherwise? -- Jean Delvare _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
