On Tue, 2023-11-07 at 06:34 -0800, Guenter Roeck wrote: > On 11/7/23 05:18, Werner Fischer wrote: > > > * What is the reason, why WDTCTRL is set to 0x00 in the code? and > > > * Could we think about removing this (at least for IT8784/8786)? > > It seems to me that setting WDTCTRL to 0x00 has been in the code > > from the beginning. > > > > For my test systems with IT8784 and IT8786 I got the following > > information from the system vendor: > > "71H bit 3 is the mode choice for the clock input of the > > IT8784/IT8786 chip. This bit is set to 1 (= PCICLK mode) and can > > not be set to 0." > > Setting it to 0 breaks the watchdog functionality. > > > > Unfortunately, ITE does not provide the specifications PDFs > > publicly anymore. But the documentation at [2] provides details > > regarding the > They really never did, or at least not for a long time. Some board > vendors used to be Linux-friendly and provided datasheets on request, > but that is no longer the case. My recommendation used to be, and > still is, not to use boards with Super-IO chips from ITE to run > Linux. This is not only due to lack of datasheets, but also due to > the lack of support from both chip and board vendors if there are any > issues when trying to support the chips in Linux. Fortunately, the manufacturer of my test systems supports me very well here. I will simply try to improve the watchdog support for the chips in the test systems. Currently I have four different boards, containing one of IT8613, IT8659, IT8784 and IT8786. > > Bit 4..7 of the register are used to control watchdog timer resets > (pings). Skipping the write entirely is therefore unacceptable even > for IT8784/IT8786 because we _don't_ want activity on a (legacy) > keyboard, mouse, game, or infrared port to reset the watchdog timer. Thanks for the explanation. Understood. > > So my idea to be on the safe side for exiting users of it87_wdt, > > too: > > * What do you think about an optional module parameter to let the > > user choose to leave WDTCTRL untouched? (this would make the > > watchdog work e.g. with my test systems with IT8784 and IT8786, > > too) > Make it conditional for IT8784/IT8786: On those chips, read the value > from the chip and clear all but bit 3. This is the safest we can do. > Future chips can be added as needed. This is a great idea, thank you very much for that. I am trying to write a corresponding patch. Werner
