From b5f93cb5133d3ad517afef541502c6c9aecf8e5d Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Mon, 10 Oct 2016 11:17:15 -0300 Subject: [PATCH] [media] stk-webcam: don't use stack for DMA The USB control messages require DMA to work. We cannot pass a stack-allocated buffer, as it is not warranted that the stack would be into a DMA enabled area. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/stkwebcam/stk-webcam.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/media/usb/stkwebcam/stk-webcam.c b/drivers/media/usb/stkwebcam/stk-webcam.c index db200c9d796d..22a9aae16291 100644 --- a/drivers/media/usb/stkwebcam/stk-webcam.c +++ b/drivers/media/usb/stkwebcam/stk-webcam.c @@ -147,20 +147,26 @@ int stk_camera_write_reg(struct stk_camera *dev, u16 index, u8 value) int stk_camera_read_reg(struct stk_camera *dev, u16 index, int *value) { struct usb_device *udev = dev->udev; + unsigned char *buf; int ret; + buf = kmalloc(sizeof(u8), GFP_KERNEL); + if (!buf) + return -ENOMEM; + ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), 0x00, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, 0x00, index, - (u8 *) value, + buf, sizeof(u8), 500); - if (ret < 0) - return ret; - else - return 0; + if (ret >= 0) + memcpy(value, buf, sizeof(u8)); + + kfree(buf); + return ret; } static int stk_start_stream(struct stk_camera *dev) -- 2.45.2