On Tue, Jun 23, 2015 at 12:13:47PM +0200, Arnd Bergmann wrote: > On Sunday 21 June 2015 19:12:09 Gaston Gonzalez wrote: > > /* WMM spec P.11: The minimum value for AIFSN shall be 2 */ > > qos_param->aifs[aci] = (qos_param->aifs[aci] < 2) ? 2:qos_param->aifs[aci]; > > > > - qos_param->cw_min[aci] = ac_params->ecw_min_max & 0x0F; > > + qos_param->cw_min[aci] = > > + cpu_to_le16(ac_params->ecw_min_max & 0x0F); > > > > - qos_param->cw_max[aci] = (ac_params->ecw_min_max & 0xF0) >> 4; > > + qos_param->cw_max[aci] = > > + cpu_to_le16((ac_params->ecw_min_max & 0xF0) >> 4); > > > > qos_param->flag[aci] = > > (ac_params->aci_aifsn & 0x10) ? 0x01 : 0x00; > > - qos_param->tx_op_limit[aci] = le16_to_cpu(ac_params->tx_op_limit); > > + qos_param->tx_op_limit[aci] = ac_params->tx_op_limit; > > } > > return 0; > > This certainly needs a more thorough description of how you determined that > the byte swaps that you add are in fact required. Did you test it on > a big-endian machine? > > Arnd Hello Arnd, Thank you for reviewing this. After your email and reviwing this again I'm getting a bit suspicious myself, but this is what I saw: -- First warning: qos_param->cw_min[aci] is defined as __le16() in ieee80211.h (ieee80211_qos_parameters structure) ac_params-> ecw_min_max is defined as u8 in ieee80211.h (ieee80211_qos_ac_parameter structure) So the assignment is: __le16 = u8 & 0x0F; -- Second warning: qos_param->cw_max[aci] is __le16() ac_params-> ecw_min_max is u8 The assignment is: __le16 = (u8 & 0xF0) >> 4; Thus, for the warning 1 and 2, I understand that the result won't be the same if the machine is big-endian or little-endian, and that's why we need a cpu_to_le16. Am I missing something? -- Third warning: In this case both sides of the assignment are already defined as __le16: qos_param->tx_op_limit[aci] (ieee80211_qos_parameters structure defined in ieee80211.h)) ac_params->tx_op_limit (ieee80211_qos_ac_parameter structure defined in ieee80211.h) So the assignment is: __le16() = le16_to_cpu(__le16) Im getting suspicious now, but it sounded wrong to me. In the case the right part is correct, I guess the left part should be u16 type? Regarding the test: I tested it on my machine, but is of course little- endian :( I could built a qemu virtual machine to test it on a big-endian emulated platform. Should that work? Regards, Gaston _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
