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Message-ID: <9038ce90-ac53-93e7-ce65-57f6ff1e9b30@nvidia.com> Date: Mon, 6 Apr 2020 10:02:21 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL101.nvidia.com (172.20.187.10) To DRHQMAIL107.nvidia.com (10.27.9.16) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable Content-Language: en-US DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1586192530; bh=HfFYbZ27Y3G9qeqPpSUfK2Y8xI+FtOmG03YNSGTQO5A=; h=X-PGP-Universal:Subject:From:To:CC:References:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Transfer-Encoding: Content-Language; b=YyDSywQDN5DN9997fHeifJqQw45hpq4ld2U+BcVuvYtKOISyV6Od2775CIfD3mZbP EIGF+B+xppN6j7RV9i4fnAE8TX5o2xJoqujYSu6KN2CysFT3uOKEB4YXyvAOZ6WjA5 YehsHQkwJvoBCfvVxyQHHDlYtdXkWtY/Q5cXBWNK7654QMQJRpGS0SEZqcDVrr3lrb QK3mILrCBrNAxnZ/qF9oAlZcqUOsoO+GNhaM3uWHGtBiGqV/CfDy/468tBvFgr0yGq KyIhhWcxvTmjXTf4EW53HyUNf+1YKhuyyZEd3NeY25/379u8dDRaXRl51bcA+9JWQM rGN8RbTyJ3S0g== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/6/20 9:37 AM, Sowjanya Komatineni wrote: > > On 4/6/20 9:29 AM, Dmitry Osipenko wrote: >> External email: Use caution opening links or attachments >> >> >> 06.04.2020 19:12, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>> On 4/6/20 9:05 AM, Dmitry Osipenko wrote: >>>> External email: Use caution opening links or attachments >>>> >>>> >>>> 06.04.2020 18:35, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>> ... >>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0 /* wait for syncpt counter to reach frame= start event >>>>>>> threshold */ >>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0 err =3D host1x_syncpt_wait(chan->frame_st= art_sp, thresh, >>>>>>> + TEGRA_VI_SYNCPT_WAIT_TIMEOUT, &value); >>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0 if (err) { >>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0 dev_err(&chan->video.dev, >>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 "frame start syncpt = timeout: %d\n", err); >>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0 /* increment syncpoint counter for timedout events */ >>>>>>> + host1x_syncpt_incr(chan->frame_start_sp); >>>>>> Why incrementing is done while hardware is still active? >>>>>> >>>>>> The sync point's state needs to be completely reset after resetting >>>>>> hardware. But I don't think that the current upstream host1x driver >>>>>> supports doing that, it's one of the known-long-standing problems of >>>>>> the >>>>>> host1x driver. >>>>>> >>>>>> At least the sp->max_val incrementing should be done based on the >>>>>> actual >>>>>> syncpoint value and this should be done after resetting hardware. >>>>> upstream host1x driver don't have API to reset or to equalize max=20 >>>>> value >>>>> with min/load value. >>>>> >>>>> So to synchronize missed event, incrementing HW syncpt counter. >>>>> >>>>> This should not impact as we increment this in case of missed events >>>>> only. >>>> It's wrong to touch sync point while hardware is active and it's=20 >>>> active >>>> until being reset. >>>> >>>> You should re-check the timeout after hw resetting and manually put=20 >>>> the >>>> syncpoint counter back into sync only if needed. >>> There is possibility of timeout to happen any time even during the >>> capture also and is not related to hw reset. >>> >>> Manual synchronization is needed when timeout of any frame events=20 >>> happen >>> otherwise all subsequence frames will timeout due to mismatch in event >>> counters. >> My point is that hardware is stopped only after being reset, until then >> you should assume that sync point could be incremented by HW at any=20 >> time. >> >> And if this happens that HW increments sync point after the timeout, >> then the sync point counter should become out-of-sync in yours case, >> IIUC. Because host1x_syncpt_incr() doesn't update the cached counter. > > We wait for enough time based on frame rate for syncpt increment to=20 > happen and if it doesn't happen by then definitely its missed event=20 > and we increment HW syncpoint for this timed event. > > cached value gets updated during syncpt wait for subsequent event. > > syncpt increment happens for all subsequent frame events during video=20 > capture. > Just to be clear, syncpt max value increment happens first and syncpt=20 trigger condition is programmed. hw syncpt increment happens based on HW=20 events. Wait time for HW syncpt to reach threshold is tuned to work for all=20 frame rates. So if increment doesn't happen by then, its definitely=20 missed event. In case of missed HW event corresponding to syncpt condition, hw syncpt=20 increment does not happen and driver increments it on timeout. As there is not API to equialize max with min incase of timeout/reset,=20 incrementing HW syncpt for timed out event. syncpt cached value gets updated during syncpt wait when it loads from=20 HW syncpt. As syncpt condition is already triggered, without compensating timeout=20 events or leaving syncpt max and hw syncpt in non synchronized state for=20 missed events, subsequent streamings will all timeout even on real events.