On Tue, Jan 2, 2018 at 7:46 AM, Baruch Siach <baruch@xxxxxxxxxx> wrote: > Hi Javad Karabi, > > On Mon, Jan 01, 2018 at 05:18:00PM -0600, Javad Karabi wrote: >> On Mon, Jan 1, 2018 at 12:14 AM, Baruch Siach <baruch@xxxxxxxxxx> wrote: >> > On Sun, Dec 31, 2017 at 03:58:57PM -0600, Javad Karabi wrote: >> >> On Sun, Dec 31, 2017 at 12:25 AM, Baruch Siach <baruch@xxxxxxxxxx> wrote: >> >> > Added linux-input list to Cc. >> >> > >> >> > On Sat, Dec 30, 2017 at 05:10:06PM -0600, Javad Karabi wrote: >> >> > > im trying to figure out why i get like 7000 interrupts a second simply by >> >> > > resting my finger on the touchpad (not even moving it) >> >> > > this is on a xps 15 9560 >> >> > > and the touchpad is at >> >> > > DLL07BE:01 06CB:7A13 Touchpad as >> >> > > /devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-7/ >> >> > i2c-DLL07BE:01/0018:06CB:7A13.0009/input/input58 >> >> > > >> >> > > could you provide me with any advice as to where i should look to figure >> >> > > this out? >> >> > > i have already tried adding code to i2c-designware-platdrv.c >> >> > > i added >> >> > > dev->clk_freq = 100000; >> >> > > in dw_i2c_plat_probe, but it still shoots off thousands of interrupts a >> >> > > second (and they are apparently spurious interrupts, atleast accoding >> >> > > to /proc/irq/17/spurious >> >> > > >> >> > > could you provide any guidance at all? would be much appreciated.. i >> >> > > would love to fix this issue and get it upstreamed in the kernel if >> >> > > possible. >> >> > > thank you >> >> > >> >> > i2c_designware is a I2C bus master driver. It allows the host to >> >> > communicate with various devices. Your touchpad is apparently one such >> >> > device. But each device on the I2C bus needs its own driver. I have no >> >> > idea which driver handles your touchpad device. Maybe someone on the >> >> > linux-input list knows. >> >> > >> >> > Specifically, the interrupts handling has nothing to do with the I2C bus. >> >> > Unlike PCIe, I2C provides no in-bus interrupt delivery facility. I2C >> >> > devices usually use a separate dedicated interrupt line. So the spurious >> >> > interrupts that you see must be handled at the touchpad input driver >> >> > level. >> >> > >> >> > One thing that might help others help you is the version of the kernel you >> >> > are running. Please provide the output of 'uname -rv' on your machine. >> >> >> >> uname -rv >> >> 4.15.0-rc5 #2 SMP Thu Dec 28 18:21:06 CST 2017 >> >> >> >> for what its worth, i think it might be hid_multitouch that is handling the >> >> touchpad, since when i rmmod it, my touchpad is no longer active. >> > >> > The hid-multitouch driver handles USB devices, not I2C. The code at >> > drivers/hid/hid-multitouch.c shows a few supported USB_VENDOR_ID_SYNAPTICS >> > (0x06cb) devices, but the 0x7a13 device ID does not appear there as of >> > v4.15-rc6. Maybe your kernel is patched to add support for that device. >> > >> > I guess that i2c_designware appears on the device hierarchy because the >> > "smart" USB hub on your system is controlled over the I2C bus. >> > >> >> when you say that the touchpad driver handles the irq stuff... i am a >> >> little confused because i2c-designware-platdrv.c contains this line: >> >> irq = platform_get_irq(pdev, 0); >> > >> > Do you have an indication that irq 17 belongs to i2c-designware? >> > >> > The i2c-designware driver uses an interrupt to handle its hardware buffer, and >> > to receive transactions status. I2C is a slow protocol, so most controller >> > implementations are asynchronous. If this irq misbehaves, then there is most >> > likely a problem with the i2c-designware driver. >> > >> >> i would assume that hid_multitouch would contain irq related code if i am >> >> understanding you correctly? >> >> am i misunderstanding? >> > >> > Since hid-multitouch is a USB driver, the irq handle itself is in the USB bus >> > driver. >> >> uname -rv: >> 4.15.0-rc5-00248-gf39d7d78b70e #2 SMP Sun Dec 31 18:17:25 CST 2017 >> >> the git commit i am at is f39d7d78b70e0f39facb1e4fab77ad3df5c52a35 >> >> > Do you have an indication that irq 17 belongs to i2c-designware? >> from /proc/interrupts: >> 17: 47105193 0 0 0 0 >> 0 0 0 IR-IO-APIC 17-fasteoi idma64.1, >> i2c_designware.1 >> >> if i rmmod idma64, the behavior remains the same, so im assuming this >> is all i2c_designware thats causing this problem. >> >> > then there is most likely a problem with the i2c-designware driver. >> do you have any idea what the problem might be? i know i should look >> in the code for i2c-designware, but why would a touchpad be shooting >> off interrupts like that with my finger simply resting on it? > > It is not the touchpad that shoots the interrupts. It is the i2c-designware > hardware module. > >> i have a theory, could you tell me if this makes sense? >> perhaps the touchpad hardware is configured with a very high >> sensitivity. so in theory if the sensitivity was decreased, then >> resting my finger would not trigger interrupts until i move it a >> larger amount? > > I don't think that the touchpad sensitivity has anything to do with this > interrupts storm. > > There is another possibility. The USB hub controller driver might be shooting > i2c transactions at the USB hub. In this case the bug is not in the i2c master > driver. > > Can you identify the driver that initiates the i2c transactions? > > baruch > > -- > http://baruch.siach.name/blog/ ~. .~ Tk Open Systems > =}------------------------------------------------ooO--U--Ooo------------{= > - baruch@xxxxxxxxxx - tel: +972.52.368.4656, http://www.tkos.co.il - > The USB hub controller driver might be shooting > i2c transactions at the USB hub. In this case the bug is not in the i2c master > driver. im still rather confused about the relationship between the i2c bus and the usb bus. from what i understand, you have the i2c bus, which has a touchpad, and the touchpad sends i2c transactions when an event has occured, e.g. i moved my finger on the touchpad... is that correct? > Can you identify the driver that initiates the i2c transactions? i would be more than happy to identify that driver if you could point me in the right direction to figure that out
