On 12/2/2012 8:20 PM, Chen Gang wrote: > pardon (I am just learning) > does 65535 mean HDLC_MAX_FRAME_SIZE ? > why do we need info->max_frame_size >= 4096 ? > in drivers/tty/synclink_gt.c: > 3550 if (info->max_frame_size < 4096) > 3551 info->max_frame_size = 4096; > 3552 else if (info->max_frame_size > 65535) > 3553 info->max_frame_size = 65535; > 3554 > ... > 3603 info->max_frame_size = 4096;
The hardware can send and receive HDLC frames up to 64K in size. The driver defaults to 4K max frame size to save buffer space for the common case (line 3603 in alloc_dev()). The module parameter max_frame_size can override the default in add_device() (lines 3550-3554 are from add_device() range checking the module parameter) > if possible: > can we move the relative comments (which are inside function) to the > location just above ldisc_receive_buf ? The added comment from my first patch described the reuse of the data buffer as the flag buffer. Alan prefers to use a zero initialized dummy buffer for the flag buffer argument. Doing it that way, the comment is not needed. -- Paul Fulghum MicroGate Systems, Ltd. =Customer Driven, by Design= (800)444-1982 (US Sales) (512)345-7791 x102 (Direct) (512)343-9046 (Fax) Central Time Zone (GMT -6h) www.microgate.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
