On Mon, Jan 1, 2018 at 12:14 AM, Baruch Siach <baruch@xxxxxxxxxx> wrote: > Hi Javad Karabi, > > Added linux-i2c to Cc. > > 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 touchpad, since when i rmmod it, my touchpad is no longer active.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. > > baruch > > -- > http://baruch.siach.name/blog/ ~. .~ Tk Open Systems > =}------------------------------------------------ooO--U--Ooo------------{= > - baruch@xxxxxxxxxx - tel: +972.2.679.5364, http://www.tkos.co.il - 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? 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? -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
