On Thu, Jan 14, 2016 at 10:33:53PM +0100, Imre Vadasz wrote:
> In iwm(4), IWM_MAX_PAYLOAD_SIZE needs to be at least one byte smaller.
>
> "IWM_MAX_CMD_PAYLOAD_SIZE + sizeof(struct iwm_cmdheader)" must be smaller
> than 4096, otherwise the payload length could get truncated to 0 in this
> assignment from iwm_send_cmd(), because 4096 doesn't fit into 12 bits:
>
> desc->tbs[0].hi_n_len = htole16(iwm_get_dma_hi_addr(paddr)
> | ((sizeof(cmd->hdr) + paylen) << 4));
>
>
> Also, in Linux's iwlwifi in iwl-fh.h (at the "struct iwl_tfd" declaration),
> there is a comment that
> "Each buffer has max size of (4K - 4)."
> So it seems logical to make IWM_MAX_CMD_PAYLOAD_SIZE 4 bytes smaller:
Committed, thanks! (and sorry for the delay)
> Index: sys/dev/pci/if_iwmreg.h
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/if_iwmreg.h,v
> retrieving revision 1.9
> diff -u -r1.9 if_iwmreg.h
> --- sys/dev/pci/if_iwmreg.h 14 Dec 2015 08:34:56 -0000 1.9
> +++ sys/dev/pci/if_iwmreg.h 14 Jan 2016 21:14:13 -0000
> @@ -5231,7 +5231,7 @@
> };
>
> #define IWM_DEF_CMD_PAYLOAD_SIZE 320
> -#define IWM_MAX_CMD_PAYLOAD_SIZE (4096 - sizeof(struct iwm_cmd_header))
> +#define IWM_MAX_CMD_PAYLOAD_SIZE ((4096 - 4) - sizeof(struct iwm_cmd_header))
> #define IWM_CMD_FAILED_MSK 0x40
>
> struct iwm_device_cmd {
>
