[flashrom] [PATCH] Break endless loop in serialport_write().
Idwer Vollering
vidwer at gmail.com
Thu Nov 29 17:43:50 CET 2012
2012/11/29 Stefan Tauner <stefan.tauner at student.tuwien.ac.at>:
> serialport_write could loop endlessly when used with a seemingly valid port
> that does always return 0 on writes instead of an error.
> Give up after about 125 ms i.e. 250 tries with a period of 500 us.
>
> Signed-off-by: Stefan Tauner <stefan.tauner at student.tuwien.ac.at>
Note that this introduces a minor execution slowdown when used with -o/--output.
Acked-by: Idwer Vollering <vidwer at gmail.com>
> ---
> serial.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/serial.c b/serial.c
> index 7e47dcc..794763e 100644
> --- a/serial.c
> +++ b/serial.c
> @@ -262,6 +262,7 @@ int serialport_write(unsigned char *buf, unsigned int writecnt)
> #else
> ssize_t tmp = 0;
> #endif
> + unsigned int empty_writes = 250; /* results in a ca. 125ms timeout */
>
> while (writecnt > 0) {
> #ifdef _WIN32
> @@ -273,9 +274,16 @@ int serialport_write(unsigned char *buf, unsigned int writecnt)
> msg_perr("Serial port write error!\n");
> return 1;
> }
> - if (!tmp)
> - msg_pdbg("Empty write\n");
> - writecnt -= tmp;
> + if (!tmp) {
> + msg_pdbg2("Empty write\n");
> + empty_writes--;
> + programmer_delay(500);
> + if (empty_writes == 0) {
> + msg_perr("Serial port seems dead!\n");
> + return 1;
> + }
> + }
> + writecnt -= tmp;
> buf += tmp;
> }
>
> --
> Kind regards, Stefan Tauner
>
>
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