Return-path: Received: from mail2.candelatech.com ([208.74.158.173]:35344 "EHLO mail2.candelatech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752536AbcFCQq5 (ORCPT ); Fri, 3 Jun 2016 12:46:57 -0400 Subject: Re: [PATCH 2/2] ath10k: remove 10.1 firmware support To: "Valo, Kalle" References: <20160603153328.11947-1-rmanohar@qti.qualcomm.com> <20160603153328.11947-2-rmanohar@qti.qualcomm.com> <5751A6D5.7080901@candelatech.com> <743182bcbd1efbdb576bcc51b0215300@codeaurora.org> <87shwuuuct.fsf@kamboji.qca.qualcomm.com> <5751AE44.8050607@candelatech.com> <87oa7iut9x.fsf@kamboji.qca.qualcomm.com> Cc: Rajkumar Manoharan , "linux-wireless@vger.kernel.org" , "Manoharan, Rajkumar" , "ath10k@lists.infradead.org" From: Ben Greear Message-ID: <5751B480.2060106@candelatech.com> (sfid-20160603_184700_390103_9DB5E8ED) Date: Fri, 3 Jun 2016 09:46:56 -0700 MIME-Version: 1.0 In-Reply-To: <87oa7iut9x.fsf@kamboji.qca.qualcomm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 06/03/2016 09:33 AM, Valo, Kalle wrote: > Ben Greear writes: > >>>> Is it possible to upgrade CT firmware to 10.2 WMI/HTT interfaces? >>> >>> That's a good idea. That shouldn't be too hard, right? I don't think HTT needs >>> any changes, but for WMI few commands and ids need to be changed. >> >> I was thinking the 10.2 mgt-over-htt API would be trouble-some to make work on >> 10.1 firmware. > > Yeah, that would be harder. But I don't see Rajkumar removing support > for that (yet) or am I missing something? What I mean is that to just make my 10.1 firmware act like 10.2 would require my 10.1 to suddenly support 10.2's mgt-over-htt. I think that will be difficult, and there is plenty of risk that some subtle WMI change would cause hard-to-detect bugs. I have done an initial port of my 10.1 changes to 10.2, it is just that the result is poor, and so I quit messing with 10.2 and re-focussed on 10.1 for the time being. Another way to help with this problem in general is to quit adding so many new firmware API. It is a lot easier to make a new firmware backwards compat than it is to make an old firmware forwards compat. When you are designing your WMI changes in new firmware, do it with care, and then you can reuse the vast bulk of your driver. I managed to add quite a few new features to my 10.1 in this manner, and the driver patches (mostly keyed off of feature flags) are not that invasive. Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com