Re: [PATCH] V4L Driver for AVerMedia USB FM Radio

Am Donnerstag 11 Oktober 2007 schrieb Faidon Liambotis:
> Add a Video4Linux driver for AVerMedia's USB FM radio.
> 
> Signed-off-by: Faidon Liambotis <[email protected]>
> ---

+/* Low-level device interface begins here */
+static int amusb_command_raw(struct amusb_device *radio, char cmd, char arg,
+                            int args, int extrabytes)
+{
+       int retv, wrotelen;
+       char b[8] = {
+               0x00, 0x55, 0xaa,
+               args,
+               cmd, arg,
+               0x00,
+               extrabytes
+       };
+
+       retv = usb_bulk_msg(radio->usbdev, usb_sndbulkpipe(radio->usbdev, 0x02),
+                           b, sizeof(b), &wrotelen, 300);

You are doing DMA on the stack. You must allocate b with kmalloc().

+/* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
+static int amusb_setfreq(struct amusb_device *radio, int freq)
+{
+       char b[3];
+
+       radio->curfreq = freq;
+       freq = (freq + FREQ_MAGIC_OFFSET) / 200; /* V4L -> tuner frequency */
+
+       b[0] = (freq >> 8) & 0xff;
+       b[1] = freq & 0xff;

1. Again DMA on the stack
2. Please use cpu_to_le16

+/* return the current frequency */
+static int amusb_getfreq(struct amusb_device *radio)
+{
+       int retv, f;
+       unsigned char b[8];
+       retv = amusb_function(radio, AMUSB_GET_FREQ, 0, b, 8);
+       if (retv < 8)
+               return retv;
+
+       f = b[1] * 0xff + b[2];

Please use le16_to_cpu()

+/* Video4Linux v2 interface */
+static int usb_amusb_do_ioctl(struct inode *inode, struct file *file,
+                               unsigned int cmd, void *arg)
+{
+       struct amusb_device *radio = video_get_drvdata(video_devdata(file));
+
+       if (!radio)
+               return -EIO;

Better -ENODEV. There's no use hiding the reason

	Regards
		Oliver

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