On Fri, Feb 22, 2019 at 11:23:35AM +0100, Wolfram Sang wrote: > On Fri, Feb 22, 2019 at 11:15:59AM +0100, Benjamin Tissoires wrote: > > On Fri, Feb 22, 2019 at 12:26 AM Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote: > > > On Tue, Feb 19, 2019 at 11:30:27AM -0800, Jim Broadus wrote: > > > > A previous change allowed I2C client devices to discover new IRQs upon > > > > reprobe by clearing the IRQ in i2c_device_remove. However, if an IRQ was > > > > assigned in i2c_new_device, that information is lost. > > > > > > > > For example, the touchscreen and trackpad devices on a Dell Inspiron laptop > > > > are I2C devices whose IRQs are defined by ACPI extended IRQ types. The > > > > client device structures are initialized during an ACPI walk. After > > > > removing the i2c_hid device, modprobe fails. > > > > > > > > This change caches the initial IRQ value in i2c_new_device and then resets > > > > the client device IRQ to the initial value in i2c_device_remove. > > > > > > > > Fixes: 6f108dd70d30 ("i2c: Clear client->irq in i2c_device_remove") > > > > Signed-off-by: Jim Broadus <jbroadus@xxxxxxxxx> > > > > > > Adding Benjamin to CC > > > > Sorry, I should have answered earlier. > > > > I am a little bit hesitant regarding this patch. The effect is > > correct, and I indeed realized a few weeks ago that something were > > wrong as we couldn't rmmod/modprobe i2c-hid. > > > > But I still have the feeling that the problem is not solved at the > > right place. In i2c_new_device() we are storing parts of the fields of > > struct i2c_board_info, and when resetting the irq we are losing > > information. This patch solves that, but I wonder if the IRQ should > > not be 'simply' set in i2c_device_probe(). This means we also need to > > store the .resources of info, but I have a feeling this will be less > > error prone in the future. > > > > But this is just my guts telling me something is not right. I would > > perfectly understand if we want to get this merged ASAP. > > > > So given that the code is correct, this is my: > > Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> > > > > But at least I have expressed my feelings :) > > Which I can relate to very much. I see the code solves the issue but my > feeling is that we are patching around something which should be handled > differently in general. > > Is somebody willing to research this further? > > Thanks for your input. > I would be willing to have more of a look at it but am slightly nervous I am not right person as all the systems I currently work with are DT based so don't really exemplify the issue at all. Thanks, Charles