Re: [PATCH 11/14] HID: sony: remove hid_output_raw_report calls

[Benjamin Tissoires]

On Wed, Feb 12, 2014 at 5:47 AM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote:
> Hi
>
> On Mon, Feb 10, 2014 at 6:58 PM, Benjamin Tissoires
> <benjamin.tissoires@xxxxxxxxxx> wrote:
>> We can not directly change the underlying struct hid_ll_driver here
>> as we did for hdev->hid_output_raw_report.
>> So allocate a struct ll_driver, and replace the old one when removing
>> the device.
>> To get a fully functional driver, we must also split the function
>> sixaxis_usb_output_raw_report() in 2, one regarding output_report, and
>> the other for raw_request.
>
> Sorry, i cannot follow here. Could you explain why this is needed? And

Well, as mentioned in the original comments, the sixaxis has two problem:
- when you send an output report, you should call hid_hw_raw_request
instead (though there is an interrupt output endpoint)
- when you send a raw_request, you should drop the reportID in the
buffer you are sending, but keep it in the SET_REPORT call... (quite
annoying).

Splitting this in two (it was all implemented in hid_output_report)
allows to transparently use the hid_hw_call, not matter who calls
what.

> I also don't think you're supposed to change the ll_driver unlocked.
> The real ll_driver might access it in any way. I don't think we do it
> right now, but it might happen.

Yeah, I am not a big fan of this either. My other concern regarding
that is the dependency against usb, while it could be a uHID device.

>
> Why can't we introduce QUIRK flags that make HID core drop the
> report_id for outgoing messages?

I did not want to come with because it would make the bright new
ll_transport interface ugly, but this may be the only way to have
something generic and drop the usb dependency and the races that may
appears (plus the ugly alloc/free).

Cheers,
Benjamin

>
> Thanks
> David
>
>> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
>> ---
>>  drivers/hid/hid-sony.c | 75 ++++++++++++++++++++++++++++++++++----------------
>>  1 file changed, 52 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
>> index d980943..dbbcd0c8 100644
>> --- a/drivers/hid/hid-sony.c
>> +++ b/drivers/hid/hid-sony.c
>> @@ -507,6 +507,8 @@ struct sony_sc {
>>         struct work_struct state_worker;
>>         struct power_supply battery;
>>
>> +       struct hid_ll_driver *prev_ll_driver;
>> +
>>  #ifdef CONFIG_SONY_FF
>>         __u8 left;
>>         __u8 right;
>> @@ -760,38 +762,52 @@ static int sony_mapping(struct hid_device *hdev, struct hid_input *hi,
>>
>>  /*
>>   * The Sony Sixaxis does not handle HID Output Reports on the Interrupt EP
>> - * like it should according to usbhid/hid-core.c::usbhid_output_raw_report()
>> + * like it should according to usbhid/hid-core.c::usbhid_output_report()
>>   * so we need to override that forcing HID Output Reports on the Control EP.
>> - *
>> - * There is also another issue about HID Output Reports via USB, the Sixaxis
>> - * does not want the report_id as part of the data packet, so we have to
>> - * discard buf[0] when sending the actual control message, even for numbered
>> - * reports, humpf!
>>   */
>> -static int sixaxis_usb_output_raw_report(struct hid_device *hid, __u8 *buf,
>> -               size_t count, unsigned char report_type)
>> +static int sixaxis_usb_output_report(struct hid_device *hid, __u8 *buf,
>> +               size_t count)
>> +{
>> +       return hid_hw_raw_request(hid, buf[0], buf, count, HID_OUTPUT_REPORT,
>> +               HID_REQ_SET_REPORT);
>> +}
>> +
>> +/*
>> + * There is also another issue about the SET_REPORT command via USB,
>> + * the Sixaxis does not want the report_id as part of the data packet, so
>> + * we have to discard buf[0] when sending the actual control message, even
>> + * for numbered reports, humpf!
>> + */
>> +static int sixaxis_usb_raw_request(struct hid_device *hid,
>> +                                  unsigned char reportnum, __u8 *buf,
>> +                                  size_t len, unsigned char rtype, int reqtype)
>>  {
>>         struct usb_interface *intf = to_usb_interface(hid->dev.parent);
>>         struct usb_device *dev = interface_to_usbdev(intf);
>>         struct usb_host_interface *interface = intf->cur_altsetting;
>> -       int report_id = buf[0];
>>         int ret;
>> +       u8 usb_dir;
>> +       unsigned int usb_pipe;
>>
>> -       if (report_type == HID_OUTPUT_REPORT) {
>> +       if (reqtype == HID_REQ_SET_REPORT) {
>>                 /* Don't send the Report ID */
>>                 buf++;
>> -               count--;
>> +               len--;
>> +               usb_dir = USB_DIR_OUT;
>> +               usb_pipe = usb_sndctrlpipe(dev, 0);
>> +       } else {
>> +               usb_dir = USB_DIR_IN;
>> +               usb_pipe = usb_rcvctrlpipe(dev, 0);
>>         }
>>
>> -       ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
>> -               HID_REQ_SET_REPORT,
>> -               USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
>> -               ((report_type + 1) << 8) | report_id,
>> -               interface->desc.bInterfaceNumber, buf, count,
>> +       ret = usb_control_msg(dev, usb_pipe, reqtype,
>> +               usb_dir | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
>> +               ((rtype + 1) << 8) | reportnum,
>> +               interface->desc.bInterfaceNumber, buf, len,
>>                 USB_CTRL_SET_TIMEOUT);
>>
>> -       /* Count also the Report ID, in case of an Output report. */
>> -       if (ret > 0 && report_type == HID_OUTPUT_REPORT)
>> +       /* Count also the Report ID. */
>> +       if (ret > 0 && reqtype == HID_REQ_SET_REPORT)
>>                 ret++;
>>
>>         return ret;
>> @@ -1047,7 +1063,7 @@ static void sixaxis_state_worker(struct work_struct *work)
>>         buf[10] |= sc->led_state[2] << 3;
>>         buf[10] |= sc->led_state[3] << 4;
>>
>> -       hid_output_raw_report(sc->hdev, buf, sizeof(buf), HID_OUTPUT_REPORT);
>> +       hid_hw_output_report(sc->hdev, buf, sizeof(buf));
>>  }
>>
>>  static void dualshock4_state_worker(struct work_struct *work)
>> @@ -1254,6 +1270,7 @@ static int sony_probe(struct hid_device *hdev, const struct hid_device_id *id)
>>         unsigned long quirks = id->driver_data;
>>         struct sony_sc *sc;
>>         unsigned int connect_mask = HID_CONNECT_DEFAULT;
>> +       struct hid_ll_driver *ll_driver;
>>
>>         sc = devm_kzalloc(&hdev->dev, sizeof(*sc), GFP_KERNEL);
>>         if (sc == NULL) {
>> @@ -1285,13 +1302,20 @@ static int sony_probe(struct hid_device *hdev, const struct hid_device_id *id)
>>         }
>>
>>         if (sc->quirks & SIXAXIS_CONTROLLER_USB) {
>> -               hdev->hid_output_raw_report = sixaxis_usb_output_raw_report;
>> +               ll_driver = devm_kzalloc(&hdev->dev, sizeof(*ll_driver),
>> +                                            GFP_KERNEL);
>> +               if (ll_driver == NULL)
>> +                       return -ENOMEM;
>> +               sc->prev_ll_driver = hdev->ll_driver;
>> +               *ll_driver = *hdev->ll_driver;
>> +               hdev->ll_driver = ll_driver;
>> +               ll_driver->output_report = sixaxis_usb_output_report;
>> +               ll_driver->raw_request = sixaxis_usb_raw_request;
>>                 ret = sixaxis_set_operational_usb(hdev);
>>                 INIT_WORK(&sc->state_worker, sixaxis_state_worker);
>> -       }
>> -       else if (sc->quirks & SIXAXIS_CONTROLLER_BT)
>> +       } else if (sc->quirks & SIXAXIS_CONTROLLER_BT) {
>>                 ret = sixaxis_set_operational_bt(hdev);
>> -       else if (sc->quirks & DUALSHOCK4_CONTROLLER_USB) {
>> +       } else if (sc->quirks & DUALSHOCK4_CONTROLLER_USB) {
>>                 /* Report 5 (31 bytes) is used to send data to the controller via USB */
>>                 ret = sony_set_output_report(sc, 0x05, 248);
>>                 if (ret < 0)
>> @@ -1339,6 +1363,8 @@ static int sony_probe(struct hid_device *hdev, const struct hid_device_id *id)
>>  err_close:
>>         hid_hw_close(hdev);
>>  err_stop:
>> +       if (sc->prev_ll_driver)
>> +               hdev->ll_driver = sc->prev_ll_driver;
>>         if (sc->quirks & SONY_LED_SUPPORT)
>>                 sony_leds_remove(hdev);
>>         if (sc->quirks & SONY_BATTERY_SUPPORT)
>> @@ -1351,6 +1377,9 @@ static void sony_remove(struct hid_device *hdev)
>>  {
>>         struct sony_sc *sc = hid_get_drvdata(hdev);
>>
>> +       if (sc->prev_ll_driver)
>> +               hdev->ll_driver = sc->prev_ll_driver;
>> +
>>         if (sc->quirks & SONY_LED_SUPPORT)
>>                 sony_leds_remove(hdev);
>>
>> --
>> 1.8.3.1
>>
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