[+ Ken, Jeff] On Tue, May 09, 2017 at 05:54:11PM +0300, Andy Shevchenko wrote: > On Tue, 2017-05-09 at 15:07 +0100, Lorenzo Pieralisi wrote: > > Hi guys, > > > > as a heads-up, with today mainline (commit 2868b2513aa7) I get the > > following splat on AMD Seattle, reverting the $SUBJECT commit "solves" > > the problem. > > > > My I2C knowledge is a bit limited but I am not sure I understand why > > we should be reading eg ss_hcnt/ss_lcnt depending on the dev->clk_freq > > but then i2c_dw_init() _always_ requires those values to be set for > > a given device. Again, I have no insights into I2C inner workings > > so apologies for the silly assumption/question. > > > > Please have a look into this, thanks. > > Since there is no clock defined you got a warning. IIUC there has never been a clock defined for this platform, that's the problem. The warning appeared because the commit in $SUBJECT prevents reading the ss_hcnt and ss_lcnt values from ACPI methods that are there in ACPI tables (SSCN and FMCN), because it carries out the SSCN FMCN look-up depending on the dev->clk_freq value. Before $SUBJECT commit the values were read unconditionally from SSCN and FMCN ACPI methods IIUC, again, I am no I2C expert so it is more a question than anything else. dev->clk_freq is set to 400000 by default because FW does not the contain (ie never contained) "clock-frequency" property and acpi_speed can't be ascertained through I2C resources, that's how I read what's happening. > It means either ID is not added to drivers/acpi/acpi_apd.c or > platform has wrong values and thus > dw_i2c_no_acpi_params should be expanded. > > I have no such platform, so I can't tell which one is the right fix. > But it's not a revert by my opinion. It was working before the commit in $SUBJECT was applied, AMD chaps may be able to chime in hopefully to clarify, whether that's a revert or not we shall see but with a given FW the kernel behaviour changed, it may affect other platforms too if their FW was not upgraded accordingly that's why I reported it. Thanks ! Lorenzo > > > [ 1.160597] ------------[ cut here ]------------ > > [ 1.165207] WARNING: CPU: 0 PID: 1 at drivers/i2c/busses/i2c- > > designware-core.c:293 i2c_dw_clk_rate+0x20/0x30 > > > > -- > Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
