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 <[email protected]>
---
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
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 <[email protected]>
Let's just ask the HID maintainers. Is this expected, and the correct fix ?
Thanks,
Guenter
> ---
> 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
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 <[email protected]>
>
> 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.
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
>
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 <[email protected]>
>>
>> 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
>>
>
>
>
>
On Tue, 18 Aug 2020, 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 <[email protected]>
> >
> > Let's just ask the HID maintainers. Is this expected, and the correct fix ?
>
> 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.
[ CCing Dmitry ]
Yeah, this problem popped out also in other contexts, where many Logitech
devices didn't probe properly, because of the race where the first IRQ is
dropped on the floor (after hid_device_io_start() happens, but before the
50ms timeout passess), and report descriptor never gets parsed and
populated.
As this is just a boot time micro-optimization, I am going to revert the
patch for 5.9 now, and we can try to fix this properly for next merge
window.
Thanks,
--
Jiri Kosina
SUSE Labs