Hi Heiner, Yes, that was what I was starting from. I was hoping there was now an in-situ way of replacing kernel modules without a full kernel recompile. I have tried this patch on Raspian 4.19.81 and Ubuntu 19 kernel 5.0.0-32 with no config changes. I believe it solves the main issue. However, I'm seeing another problem that I can't explain. Specifically: - On reboot, device shows up in /sys/class/hidraw/ - Opening with hidapi and (mis)using hidapi functions works, but, - Device is then removed from /sys/class/hidraw/ Under what circumstances can a device be removed from /sys/class/hidraw? If you'd like to trigger this yourself, run "blink1-tool --list" and see the blink(1) disappear. And yet "blink1-tool" can subsequently still communicate with the blink(1). Which I don't quite understand yet either. Cheers, -=Tod > On Nov 10, 2019, at 9:25 a, Heiner Kallweit <hkallweit1@xxxxxxxxx> wrote: > > On 10.11.2019 17:59, Tod E. Kurt wrote: >> Hi Heiner, (and others on the list) >> >> Thanks for your quick and detailed response. >> >> I am endeavoring to try the patch out now. But I've not built a desktop Linux kernel or kernel modules in about 15 years. Do you have a preferred recipe for applying this patch to an existing distro? Since 'hid-quirks' isn't a module, this means recompiling the entire HID driver, correct? I mostly test against various modern Ubuntu or Raspian flavors of Debian, if that matters. >> > See e.g. here: https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel > >> Also, is there a mitigation for users running production distros that doesn't involve a recompile? >> > I don't think so (at least from kernel perspective). What you could do is adding an integration with > the /sys/class/led interface in your library (if it should be suitable for your use cases) and > auto-detect which interface to use. > >> Thanks, >> -=Tod >> > Heiner > >>> On Nov 10, 2019, at 2:44 a, Heiner Kallweit <hkallweit1@xxxxxxxxx> wrote: >>> >>> On 10.11.2019 04:26, Tod E. Kurt wrote: >>>> HiI >>>> >>> Hi Tod, >>> >>>> Since you are listed as author of "hid-led.c": >>>> https://github.com/torvalds/linux/blob/master/drivers/hid/hid-led.c, >>>> I was wondering if you could offer some insight on an issue I'm seeing. >>>> I'm a maintainer of "hidapi" and "node-hid", cross-platform C and NodeJs libraries for accessing HID devices, and I'm the creator of the ThingM blink(1) USB LED that "hid-led" controls. >>>> >>>> On the distros I've seen (Ubuntu, Raspian) where "hid-led" is enabled, when inserting a blink(1) device, the "hid-led" driver appears to grab the device and remove it from available "hidraw" devices. This makes generic hidraw-based systems (like "hidapi" and the upcoming Chrome WebHID) unable to see the blink(1) >>>> >>>> I have tried blacklisting the "hid-led" module but the problem persist. Ffrom dmesg and lsmod the module does appear to not be loaded on reboot. >>>> >>>> Any insights on what's going on? Any tips on how to debug this or how to prevent this from occurring? >>>> >>> When hid-led was written it was needed to add the LED devices to hid_have_special_driver list. >>> Else the driver can't take control over the device. Side effect is that even if hid-led >>> isn't loaded hid-generic can't take control. >>> I think since e04a0442d33b ("HID: core: remove the absolute need of hid_have_special_driver[]") >>> it's no longer needed to have the LED devices in hid_have_special_driver. >>> Could you please test the following patch? If hid-led is loaded is should control the >>> device, if it's blacklisted hid-generic should have the control. >>> >>> >>> diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c >>> index c50bcd967..bdaab79f7 100644 >>> --- a/drivers/hid/hid-quirks.c >>> +++ b/drivers/hid/hid-quirks.c >>> @@ -419,13 +419,6 @@ static const struct hid_device_id hid_have_special_driver[] = { >>> #if IS_ENABLED(CONFIG_HID_LCPOWER) >>> { HID_USB_DEVICE(USB_VENDOR_ID_LCPOWER, USB_DEVICE_ID_LCPOWER_LC1000) }, >>> #endif >>> -#if IS_ENABLED(CONFIG_HID_LED) >>> - { HID_USB_DEVICE(USB_VENDOR_ID_DREAM_CHEEKY, USB_DEVICE_ID_DREAM_CHEEKY_WN) }, >>> - { HID_USB_DEVICE(USB_VENDOR_ID_DREAM_CHEEKY, USB_DEVICE_ID_DREAM_CHEEKY_FA) }, >>> - { HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_LUXAFOR) }, >>> - { HID_USB_DEVICE(USB_VENDOR_ID_RISO_KAGAKU, USB_DEVICE_ID_RI_KA_WEBMAIL) }, >>> - { HID_USB_DEVICE(USB_VENDOR_ID_THINGM, USB_DEVICE_ID_BLINK1) }, >>> -#endif >>> #if IS_ENABLED(CONFIG_HID_LENOVO) >>> { HID_USB_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_TPKBD) }, >>> { HID_USB_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_CUSBKBD) }, >>> -- >>> 2.24.0 >>> >>>> I can send you blink(1) devices and "hidapi" test programs if you'd like to try to replicate this. >>>> >>> Thanks for the offer, I've got a blink(1) already. Just tested the patch with this device >>> and it worked properly like described above. >>> >>>> Thanks! >>>> -=Tod >>> >>> Heiner >> >> >
