Hans Verkuil <hverkuil@xxxxxxxxx> writes: >> +/* >> + * >> + * The device delivers data in chunks of 0x400 bytes. >> + * The four first bytes is a magic header to identify the chunks. >> + * 0xaa 0xaa 0x00 0x00 = saa7113 Active Video Data >> + * 0xaa 0xaa 0x00 0x01 = PCM - 24Bit 2 Channel audio data >> + */ >> +static void process_packet(struct smi2021_dev *dev, u8 *p, int len) >> +{ >> + int i; >> + u32 *header; >> + >> + if (len % 0x400 != 0) { >> + printk_ratelimited(KERN_INFO "smi2021::%s: len: %d\n", >> + __func__, len); >> + return; >> + } >> + >> + for (i = 0; i < len; i += 0x400) { >> + header = (u32 *)(p + i); >> + switch (__cpu_to_be32(*header)) { > > That's not right. You probably mean __be32_to_cpu, that makes more sense. > >> + case 0xaaaa0000: { >> + parse_video(dev, p+i+4, 0x400-4); >> + break; >> + } >> + case 0xaaaa0001: { >> + smi2021_audio(dev, p+i+4, 0x400-4); >> + break; >> + } This could be just me, but I would have done it like this to take advantage of compile time constant conversions (and also dropping the noisy extra {}s): switch (*header) { case cpu_to_be32(0xaaaa0000): parse_video(dev, p+i+4, 0x400-4); break; case cpu_to_be32(0xaaaa0001): smi2021_audio(dev, p+i+4, 0x400-4); break; .. >From the name of the function I assume the difference may actually be measurable here if this runs for every processed packet. Bjørn -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html