* Questions about implementing hid driver or input driver
@ 2012-09-07 5:24 Axel Lin
2012-09-07 6:43 ` Dmitry Torokhov
0 siblings, 1 reply; 3+ messages in thread
From: Axel Lin @ 2012-09-07 5:24 UTC (permalink / raw)
To: linux-input; +Cc: Jiri Kosina, Dmitry Torokhov
Hi list,
I have a tablet that shows it is a HID device.
But the report descriptor looks broken.
Below shows the device information:
lsusb -v:
Bus 002 Device 004: ID 04b4:3045 Cypress Semiconductor Corp.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x04b4 Cypress Semiconductor Corp.
idProduct 0x3045
bcdDevice 1.00
iManufacturer 1 Ping-IT
iProduct 2 RS232_USB
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 34
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 3 Bus power
bmAttributes 0xa0
(Bus Powered)
Remote Wakeup
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 0 No Subclass
bInterfaceProtocol 0 None
iInterface 4 HID
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 1.10
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 26
Report Descriptors:
** UNAVAILABLE **
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 10
Device Status: 0x0000
(Bus Powered)
And below is the report descriptor ( by usbhid-dump / hidrd-convert )
0x05, 0x0D, /* Usage Page (Digitizer), */
0x09, 0x08, /* Usage (3D Digitizer), */
0xA1, 0x01, /* Collection (Application), */
0x09, 0x01, /* Usage (Digitizer), */
0xA1, 0x00, /* Collection (Physical), */
0x05, 0x01, /* Usage Page (Desktop), */
0x09, 0x3B, /* Usage (Byte Count), */
0x15, 0x00, /* Logical Minimum (0), */
0x25, 0x7F, /* Logical Maximum (127), */
0x75, 0x08, /* Report Size (8), */
0x95, 0x07, /* Report Count (7), */
0x81, 0x02, /* Input (Variable), */
0xC0, /* End Collection, */
0xC0 /* End Collection */
The report descriptor looks broken to me:
1. The report descriptor does not have Usage for TOOL_PEN/STYLUS/STYLUS2/PRESSURE,
so evdev doest not recognized it as a tablet.
Actually, the report descriptor does not define any detail of the data.
It only shows a 7 bytes report content.
2. It does not have Report ID field.
(Does it make sense to have a report descriptor without Report ID field?)
So in this case, should I implement a HID (special device) driver or
a input driver (in drivers/input/tablet folder) for this device?
Regards,
Axel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Questions about implementing hid driver or input driver
2012-09-07 5:24 Questions about implementing hid driver or input driver Axel Lin
@ 2012-09-07 6:43 ` Dmitry Torokhov
2012-09-07 7:21 ` Jiri Kosina
0 siblings, 1 reply; 3+ messages in thread
From: Dmitry Torokhov @ 2012-09-07 6:43 UTC (permalink / raw)
To: Axel Lin; +Cc: linux-input, Jiri Kosina
Hi Axel,
On Fri, Sep 07, 2012 at 01:24:41PM +0800, Axel Lin wrote:
> Hi list,
> I have a tablet that shows it is a HID device.
> But the report descriptor looks broken.
>
> Below shows the device information:
>
> lsusb -v:
>
> Bus 002 Device 004: ID 04b4:3045 Cypress Semiconductor Corp.
> Device Descriptor:
> bLength 18
> bDescriptorType 1
> bcdUSB 1.10
> bDeviceClass 0 (Defined at Interface level)
> bDeviceSubClass 0
> bDeviceProtocol 0
> bMaxPacketSize0 8
> idVendor 0x04b4 Cypress Semiconductor Corp.
> idProduct 0x3045
> bcdDevice 1.00
> iManufacturer 1 Ping-IT
> iProduct 2 RS232_USB
> iSerial 0
> bNumConfigurations 1
> Configuration Descriptor:
> bLength 9
> bDescriptorType 2
> wTotalLength 34
> bNumInterfaces 1
> bConfigurationValue 1
> iConfiguration 3 Bus power
> bmAttributes 0xa0
> (Bus Powered)
> Remote Wakeup
> MaxPower 100mA
> Interface Descriptor:
> bLength 9
> bDescriptorType 4
> bInterfaceNumber 0
> bAlternateSetting 0
> bNumEndpoints 1
> bInterfaceClass 3 Human Interface Device
> bInterfaceSubClass 0 No Subclass
> bInterfaceProtocol 0 None
> iInterface 4 HID
> HID Device Descriptor:
> bLength 9
> bDescriptorType 33
> bcdHID 1.10
> bCountryCode 0 Not supported
> bNumDescriptors 1
> bDescriptorType 34 Report
> wDescriptorLength 26
> Report Descriptors:
> ** UNAVAILABLE **
> Endpoint Descriptor:
> bLength 7
> bDescriptorType 5
> bEndpointAddress 0x81 EP 1 IN
> bmAttributes 3
> Transfer Type Interrupt
> Synch Type None
> Usage Type Data
> wMaxPacketSize 0x0008 1x 8 bytes
> bInterval 10
> Device Status: 0x0000
> (Bus Powered)
>
> And below is the report descriptor ( by usbhid-dump / hidrd-convert )
>
> 0x05, 0x0D, /* Usage Page (Digitizer), */
> 0x09, 0x08, /* Usage (3D Digitizer), */
> 0xA1, 0x01, /* Collection (Application), */
> 0x09, 0x01, /* Usage (Digitizer), */
> 0xA1, 0x00, /* Collection (Physical), */
> 0x05, 0x01, /* Usage Page (Desktop), */
> 0x09, 0x3B, /* Usage (Byte Count), */
> 0x15, 0x00, /* Logical Minimum (0), */
> 0x25, 0x7F, /* Logical Maximum (127), */
> 0x75, 0x08, /* Report Size (8), */
> 0x95, 0x07, /* Report Count (7), */
> 0x81, 0x02, /* Input (Variable), */
> 0xC0, /* End Collection, */
> 0xC0 /* End Collection */
>
> The report descriptor looks broken to me:
> 1. The report descriptor does not have Usage for TOOL_PEN/STYLUS/STYLUS2/PRESSURE,
> so evdev doest not recognized it as a tablet.
> Actually, the report descriptor does not define any detail of the data.
> It only shows a 7 bytes report content.
> 2. It does not have Report ID field.
> (Does it make sense to have a report descriptor without Report ID field?)
>
> So in this case, should I implement a HID (special device) driver or
> a input driver (in drivers/input/tablet folder) for this device?
>
I think because the driver would hardly use any of HID infrastructure it
would make sense to do it as an input driver.
Thanks.
--
Dmitry
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Questions about implementing hid driver or input driver
2012-09-07 6:43 ` Dmitry Torokhov
@ 2012-09-07 7:21 ` Jiri Kosina
0 siblings, 0 replies; 3+ messages in thread
From: Jiri Kosina @ 2012-09-07 7:21 UTC (permalink / raw)
To: Dmitry Torokhov; +Cc: Axel Lin, linux-input
On Thu, 6 Sep 2012, Dmitry Torokhov wrote:
> > Hi list,
> > I have a tablet that shows it is a HID device.
> > But the report descriptor looks broken.
> >
> > Below shows the device information:
> >
> > lsusb -v:
> >
> > Bus 002 Device 004: ID 04b4:3045 Cypress Semiconductor Corp.
> > Device Descriptor:
> > bLength 18
> > bDescriptorType 1
> > bcdUSB 1.10
> > bDeviceClass 0 (Defined at Interface level)
> > bDeviceSubClass 0
> > bDeviceProtocol 0
> > bMaxPacketSize0 8
> > idVendor 0x04b4 Cypress Semiconductor Corp.
> > idProduct 0x3045
> > bcdDevice 1.00
> > iManufacturer 1 Ping-IT
> > iProduct 2 RS232_USB
> > iSerial 0
> > bNumConfigurations 1
> > Configuration Descriptor:
> > bLength 9
> > bDescriptorType 2
> > wTotalLength 34
> > bNumInterfaces 1
> > bConfigurationValue 1
> > iConfiguration 3 Bus power
> > bmAttributes 0xa0
> > (Bus Powered)
> > Remote Wakeup
> > MaxPower 100mA
> > Interface Descriptor:
> > bLength 9
> > bDescriptorType 4
> > bInterfaceNumber 0
> > bAlternateSetting 0
> > bNumEndpoints 1
> > bInterfaceClass 3 Human Interface Device
> > bInterfaceSubClass 0 No Subclass
> > bInterfaceProtocol 0 None
> > iInterface 4 HID
> > HID Device Descriptor:
> > bLength 9
> > bDescriptorType 33
> > bcdHID 1.10
> > bCountryCode 0 Not supported
> > bNumDescriptors 1
> > bDescriptorType 34 Report
> > wDescriptorLength 26
> > Report Descriptors:
> > ** UNAVAILABLE **
> > Endpoint Descriptor:
> > bLength 7
> > bDescriptorType 5
> > bEndpointAddress 0x81 EP 1 IN
> > bmAttributes 3
> > Transfer Type Interrupt
> > Synch Type None
> > Usage Type Data
> > wMaxPacketSize 0x0008 1x 8 bytes
> > bInterval 10
> > Device Status: 0x0000
> > (Bus Powered)
> >
> > And below is the report descriptor ( by usbhid-dump / hidrd-convert )
> >
> > 0x05, 0x0D, /* Usage Page (Digitizer), */
> > 0x09, 0x08, /* Usage (3D Digitizer), */
> > 0xA1, 0x01, /* Collection (Application), */
> > 0x09, 0x01, /* Usage (Digitizer), */
> > 0xA1, 0x00, /* Collection (Physical), */
> > 0x05, 0x01, /* Usage Page (Desktop), */
> > 0x09, 0x3B, /* Usage (Byte Count), */
> > 0x15, 0x00, /* Logical Minimum (0), */
> > 0x25, 0x7F, /* Logical Maximum (127), */
> > 0x75, 0x08, /* Report Size (8), */
> > 0x95, 0x07, /* Report Count (7), */
> > 0x81, 0x02, /* Input (Variable), */
> > 0xC0, /* End Collection, */
> > 0xC0 /* End Collection */
> >
> > The report descriptor looks broken to me:
> > 1. The report descriptor does not have Usage for TOOL_PEN/STYLUS/STYLUS2/PRESSURE,
> > so evdev doest not recognized it as a tablet.
> > Actually, the report descriptor does not define any detail of the data.
> > It only shows a 7 bytes report content.
> > 2. It does not have Report ID field.
> > (Does it make sense to have a report descriptor without Report ID field?)
> >
> > So in this case, should I implement a HID (special device) driver or
> > a input driver (in drivers/input/tablet folder) for this device?
> >
>
> I think because the driver would hardly use any of HID infrastructure it
> would make sense to do it as an input driver.
Agreed.
It however also slightly depends on the actual data it is sending. It
might be a proper HID protocol in the end, just the report descriptor
might be completely bogus.
We already have a couple devices supported in linux by hid-waltop driver.
The only thing it does is that it replaces completely wrong report
desriptor with a proper one, and it's enough to make the device work
properly.
But that really depends on the protocol that the device is using in the
reports.
--
Jiri Kosina
SUSE Labs
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-09-07 6:43 ` Dmitry Torokhov
2012-09-07 7:21 ` Jiri Kosina
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