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net: 6pack: Fix tx timeout and slot time
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tx timeout and slot time are currently specified in units of HZ.  On
Alpha, HZ is defined as 1024.  When building alpha:allmodconfig, this
results in the following error message.

  drivers/net/hamradio/6pack.c: In function 'sixpack_open':
  drivers/net/hamradio/6pack.c:71:41: error:
  	unsigned conversion from 'int' to 'unsigned char'
  	changes value from '256' to '0'

In the 6PACK protocol, tx timeout is specified in units of 10 ms and
transmitted over the wire:

    https://www.linux-ax25.org/wiki/6PACK

Defining a value dependent on HZ doesn't really make sense, and
presumably comes from the (very historical) situation where HZ was
originally 100.

Note that the SIXP_SLOTTIME use explicitly is about 10ms granularity:

        mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100);

and the SIXP_TXDELAY walue is sent as a byte over the wire.

Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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groeck authored and torvalds committed Sep 16, 2021
1 parent 040b890 commit 3c0d2a4
Showing 1 changed file with 2 additions and 2 deletions.
4 changes: 2 additions & 2 deletions drivers/net/hamradio/6pack.c
Original file line number Diff line number Diff line change
Expand Up @@ -68,9 +68,9 @@
#define SIXP_DAMA_OFF 0

/* default level 2 parameters */
#define SIXP_TXDELAY (HZ/4) /* in 1 s */
#define SIXP_TXDELAY 25 /* 250 ms */
#define SIXP_PERSIST 50 /* in 256ths */
#define SIXP_SLOTTIME (HZ/10) /* in 1 s */
#define SIXP_SLOTTIME 10 /* 100 ms */
#define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */
#define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */

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