Re: [PATCH] HID: sony: Enable Gasia third-party PS3 controllers

[Oliver Neukum <oneukum@suse.de>]

On Sat, 2015-02-07 at 15:48 +0200, Lauri Kasanen wrote:
> Without this, my "Gasia Co.,Ltd PS(R) Gamepad" would not send
> any events. Now everything works including the leds.
> 
> Based on work by Andrew Haines and Antonio Ospite.
> 
> cc: Antonio Ospite <ao2@ao2.it>
> cc: Andrew Haines <AndrewD207@aol.com>
> Signed-off-by: Lauri Kasanen <cand@gmx.com>
> ---
>  drivers/hid/hid-sony.c | 26 ++++++++++++++++++++++++--
>  1 file changed, 24 insertions(+), 2 deletions(-)
> 
> Antonio's original approach was not enough; it enabled the events,
> but only for a few seconds, then the controller timed out and sent
> no more. Andrew's did more than was necessary. This is a combination
> of the two, against Linus' git.
> 
> diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
> index 31e9d25..de93386 100644
> --- a/drivers/hid/hid-sony.c
> +++ b/drivers/hid/hid-sony.c
> @@ -36,6 +36,7 @@
>  #include <linux/list.h>
>  #include <linux/idr.h>
>  #include <linux/input/mt.h>
> +#include <linux/usb/input.h>
>  
>  #include "hid-ids.h"
>  
> @@ -1130,8 +1131,12 @@ static void sony_input_configured(struct hid_device *hdev,
>   */
>  static int sixaxis_set_operational_usb(struct hid_device *hdev)
>  {
> +	struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
> +	struct usb_device *dev = interface_to_usbdev(intf);
>  	int ret;
> -	char *buf = kmalloc(18, GFP_KERNEL);
> +	char *buf = kmalloc(65, GFP_KERNEL);
> +	unsigned char buf2[] = { 0x00 };
> +	int transfered;
>  
>  	if (!buf)
>  		return -ENOMEM;
> @@ -1140,7 +1145,24 @@ static int sixaxis_set_operational_usb(struct hid_device *hdev)
>  				 HID_REQ_GET_REPORT);
>  
>  	if (ret < 0)
> -		hid_err(hdev, "can't set operational mode\n");
> +		hid_err(hdev, "can't set operational mode on the control EP\n");
> +
> +	/*
> +	 * Some compatible controllers like the Speedlink Strike FX and
> +	 * Gasia need another query plus an USB interrupt to get operational.
> +	 */
> +	ret = hid_hw_raw_request(hdev, 0xf5, buf, 64, HID_FEATURE_REPORT,
> +				 HID_REQ_GET_REPORT);
> +
> +	if (ret < 0)
> +		hid_err(hdev, "can't set operational mode on the interrupt EP\n");
> +
> +	ret = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x02),
> +				buf2, sizeof(buf2),
> +				&transfered, USB_CTRL_SET_TIMEOUT);

You cannot do this. Even for a single byte DMA on the stack is
wrong. Not on all architectures it works at all and you violate
the DMA constrainsts. You must use kmalloc().

	Regards
		Oliver