Re: [PATCH 04/11] HID: logitech-dj: remove hidinput_input_event

Hi

On Mon, Feb 3, 2014 at 5:21 PM, Benjamin Tissoires
[off-list ref] wrote:

On Mon, Feb 3, 2014 at 11:06 AM, David Herrmann [off-list ref] wrote:

quoted

Hi

On Sun, Feb 2, 2014 at 5:50 AM, Benjamin Tissoires
[off-list ref] wrote:

quoted

hid-logitech-dj uses its own ->hidinput_input_event() instead of
the generic binding in hid-input.
Moving the handling of LEDs towards logi_dj_output_hidraw_report()
allows two things:
- remove hidinput_input_event in struct hid_device
- hidraw user space programs can also set the LEDs

Signed-off-by: Benjamin Tissoires <redacted>
---
 drivers/hid/hid-logitech-dj.c | 99 +++++++++++++++----------------------------
 1 file changed, 35 insertions(+), 64 deletions(-)

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index f45279c..61d2bbf 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c

@@ -44,14 +44,6 @@ static const char kbd_descriptor[] = {
        0x19, 0xE0,             /*   USAGE_MINIMUM (Left Control)   */
        0x29, 0xE7,             /*   USAGE_MAXIMUM (Right GUI)      */
        0x81, 0x02,             /*   INPUT (Data,Var,Abs)       */
-       0x95, 0x05,             /*   REPORT COUNT (5)           */
-       0x05, 0x08,             /*   USAGE PAGE (LED page)      */
-       0x19, 0x01,             /*   USAGE MINIMUM (1)          */
-       0x29, 0x05,             /*   USAGE MAXIMUM (5)          */
-       0x91, 0x02,             /*   OUTPUT (Data, Variable, Absolute)  */
-       0x95, 0x01,             /*   REPORT COUNT (1)           */
-       0x75, 0x03,             /*   REPORT SIZE (3)            */
-       0x91, 0x01,             /*   OUTPUT (Constant)          */
        0x95, 0x06,             /*   REPORT_COUNT (6)           */
        0x75, 0x08,             /*   REPORT_SIZE (8)            */
        0x15, 0x00,             /*   LOGICAL_MINIMUM (0)        */

@@ -60,6 +52,18 @@ static const char kbd_descriptor[] = {
        0x19, 0x00,             /*   USAGE_MINIMUM (no event)       */
        0x2A, 0xFF, 0x00,       /*   USAGE_MAXIMUM (reserved)       */
        0x81, 0x00,             /*   INPUT (Data,Ary,Abs)       */
+       0x85, 0x0e,             /* REPORT_ID (14)               */
+       0x05, 0x08,             /*   USAGE PAGE (LED page)      */
+       0x95, 0x05,             /*   REPORT COUNT (5)           */
+       0x75, 0x01,             /*   REPORT SIZE (1)            */
+       0x15, 0x00,             /*   LOGICAL_MINIMUM (0)        */
+       0x25, 0x01,             /*   LOGICAL_MAXIMUM (1)        */
+       0x19, 0x01,             /*   USAGE MINIMUM (1)          */
+       0x29, 0x05,             /*   USAGE MAXIMUM (5)          */
+       0x91, 0x02,             /*   OUTPUT (Data, Variable, Absolute)  */
+       0x95, 0x01,             /*   REPORT COUNT (1)           */
+       0x75, 0x03,             /*   REPORT SIZE (3)            */
+       0x91, 0x01,             /*   OUTPUT (Constant)          */
        0xC0
 };

@@ -544,10 +548,30 @@ static int logi_dj_output_hidraw_report(struct hid_device *hid, u8 * buf,
                                        size_t count,
                                        unsigned char report_type)
 {
-       /* Called by hid raw to send data */
-       dbg_hid("%s\n", __func__);
+       struct dj_device *djdev = hid->driver_data;
+       struct dj_receiver_dev *djrcv_dev = djdev->dj_receiver_dev;
+       u8 *out_buf;
+       int ret;

-       return 0;
+       if (buf[0] != REPORT_TYPE_LEDS)
+               return -EINVAL;
+
+       out_buf = kzalloc(DJREPORT_SHORT_LENGTH, GFP_ATOMIC);
+       if (!out_buf)
+               return -ENOMEM;
+
+       if (count < DJREPORT_SHORT_LENGTH - 2)
+               count = DJREPORT_SHORT_LENGTH - 2;
+
+       out_buf[0] = REPORT_ID_DJ_SHORT;
+       out_buf[1] = djdev->device_index;
+       memcpy(out_buf + 2, buf, count);
+
+       ret = djrcv_dev->hdev->hid_output_raw_report(djrcv_dev->hdev, out_buf,
+               DJREPORT_SHORT_LENGTH, report_type);

Strictly speaking the code below uses HID_REQ_SET_REPORT and you
replace it with hid_output_raw_report() here (which at least for BTHID
is not equivalent). Anyhow, HID-core uses hid_output_raw_report(),
too, so this should be fine.

Yes, you are right. This fires back on me yesterday when I tried to
remove the hid_output_raw_report() calls.
It occurs it works because usbhid_out_raw_report() uses set_report
when there is no urbout, which is the case with logitech receivers.
So I guess an ideal solution would be to implement a hid_hw_request call.

However, the only concern I have with hid_hw_request is that it does
not allow hidraw to play with the LEDs given that hidraw does not have
an ioctl for SET_REPORT (or GET_REPORT). I already seen this issue
regarding i2c_hid at some point, but it was "solved" in i2c_hid by
using the same ugly trick that we have in USB-hid.

Hah! That's why it worked all the years, USB-HID checks for !urbout..
and yeah, that's what I just criticized in your i2c-hid patch.. Ok,
I'm fine if we make output_report() fall back to SET_REPORT if not
output-channel is supported. But we it gets ugly if we rely on that
from the upper stack... hmm, don't know how to make that work but
adding a hid quirk to use SET_REPORT for hidinput_input_report().

Thanks
David