I was looking at the TTY flip buffers, and I noticed that its structure
declaration is as follows:
#define TTY_FLIPBUF_SIZE 512
struct tty_flip_buffer {
struct tq_struct tqueue;
struct semaphore pty_sem;
char *char_buf_ptr;
unsigned char *flag_buf_ptr;
int count;
int buf_num;
unsigned char char_buf[2*TTY_FLIPBUF_SIZE];
char flag_buf[2*TTY_FLIPBUF_SIZE];
unsigned char slop[4]; /* N.B. bug overwrites buffer by 1 */
};
Note that the char_buf buffer size is 2*TTY_FLIPBUF_SIZE. However, all
serial drivers check the value TTY_FLIPBUF_SIZE in order to know whether
the buffer is full or not.
Is this correct?? Shouldn't the serial drivers be checking for
2*TTY_FLIPBUF_SIZE?? Aren't the serial drivers subutilizing the flip
buffers in this way??
Another question: if I want to use a larger flip buffer, can I just
allocate the required memory amount and set the pointers char_buf_ptr and
flag_buf_ptr?? If not, I don't see the reason for the existence of these
pointers ...
Thanks in advance for your comments.
Regards,
Ivan
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