On 8/18/20 6:12 AM, Marius Zachmann wrote: > On 18.08.20 at 17:35:33 CEST, Guenter Roeck wrote >> On Mon, Aug 17, 2020 at 09:00:40AM +0200, Marius Zachmann wrote: >>> Possibly because of the changes in usbhid/hid-core.c the first >>> raw input report is not received during ccp_probe function and it will >>> timeout. I am not sure, whether this behaviour is expected after >>> hid_device_io_start or if I am missing something. >>> As a solution this adds msleep(50) to ccp_probe so that all initial >>> input reports can be received. >>> >>> Signed-off-by: Marius Zachmann <mail@xxxxxxxxxxxxxxxxx> >> >> Let's just ask the HID maintainers. Is this expected, and the correct fix ? >> >> Thanks, >> Guenter >> > > This seems to be a problem with "HID: usbhid: do not sleep when opening > device". There is a bug report with some Logitech devices at the correct > thread. These drivers also use hid_device_io_start and fail. Seems to me, > this is the same problem and I retract this (not so beautiful) fix until > this is sorted out. > I even was involved in that patch. Sigh. Guenter > Thanks, > Marius > >>> --- >>> v2: >>> - fix accidentally deleted comment >>> >>> --- >>> drivers/hwmon/corsair-cpro.c | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/drivers/hwmon/corsair-cpro.c b/drivers/hwmon/corsair-cpro.c >>> index 591929ec217a..c04fac1d820f 100644 >>> --- a/drivers/hwmon/corsair-cpro.c >>> +++ b/drivers/hwmon/corsair-cpro.c >>> @@ -10,6 +10,7 @@ >>> >>> #include <linux/bitops.h> >>> #include <linux/completion.h> >>> +#include <linux/delay.h> >>> #include <linux/hid.h> >>> #include <linux/hwmon.h> >>> #include <linux/kernel.h> >>> @@ -513,6 +514,7 @@ static int ccp_probe(struct hid_device *hdev, const struct hid_device_id *id) >>> init_completion(&ccp->wait_input_report); >>> >>> hid_device_io_start(hdev); >>> + msleep(50); /* wait before events can be received */ >>> >>> /* temp and fan connection status only updates when device is powered on */ >>> ret = get_temp_cnct(ccp); >>> -- >>> 2.28.0 >> > > > >
