From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from z5.mailgun.us ([104.130.96.5]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kadAy-0006CO-R8 for ath10k@lists.infradead.org; Thu, 05 Nov 2020 11:11:35 +0000 MIME-Version: 1.0 Date: Thu, 05 Nov 2020 19:10:37 +0800 From: Carl Huang Subject: Re: [RFC 1/2] nl80211: add common API to configure SAR power limitations. In-Reply-To: <877dr0nqtv.fsf@codeaurora.org> References: <1600753017-4614-1-git-send-email-cjhuang@codeaurora.org> <877dr0nqtv.fsf@codeaurora.org> Message-ID: <728196c17b4e70e18c99798a9945d1e6@codeaurora.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "ath10k" Errors-To: ath10k-bounces+kvalo=adurom.com@lists.infradead.org To: Kalle Valo Cc: Brian Norris , linux-wireless , Doug Anderson , ath10k , ath11k@lists.infradead.org, Abhishek Kumar On 2020-11-05 16:35, Kalle Valo wrote: > Brian Norris writes: > >> + ath10k >> >> [ I realize I replied to the "wrong" RFC v1; I fell trap to Kalle's >> note: >> >> "When you submit a new version mark it as "v2". Otherwise people don't >> know what's the latest version." ] >> >> On Tue, Nov 3, 2020 at 11:32 PM Carl Huang >> wrote: >>> On 2020-11-04 10:00, Brian Norris wrote: >>> > What are the ABI guarantees around a given driver/chip's 'sar_capa'? >>> > Do we guarantee that if the driver supports N ranges of certain bands, >>> > that it will always continue to support those bands? >> ... >>> For a given chip(at least a QCOM chip), we don't see that the >>> range will grow or change. >> >> That's good to know. But that's not quite the same as an ABI >> guarantee. > > I'm not sure if I understood Brian's question correctly, but I have > concerns on the assumption that frequency ranges never change. For > example, in ath10k we have a patch[1] under discussion which adds more > channels and in ath11k we added 6 GHz band after initial ath11k support > landed. And I would not be surprised if in some boards/platforms a > certain band is disabled due to cotting costs (no antenna etc). My > preference is to have a robust interface which would be designed to > handle these kind of changes. > > [1] [PATCH] ath10k: enable advertising support for channels 32, 68 and > 98 So the trick here is even if more channels are supported, it doesn't mean that it can support different SAR setting on these new channels. In this case, it likely falls into 5G range. It's safe for driver to extend the 5G range and doesn't break userspace. (68 and 98 are already in the 5G range, so driver just extends the start edge freq to 32 here.). But for flexibility, given 6 GHz as example here, let's keep the explicit index for SET command. For sar_capa advertisement, the explicit index is dropped as Johannes suggested. New ranges can only be appended to existing ones. Like Brian said, only add or split is allowed. The complexity to handle splitted range Vs whole range is left to WLAN driver itself. Userspace can SET any ranges which are advertised by WLAN driver. It's not required to set all ranges and userspace can skip any ranges. _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k