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Thu, 03 Apr 2025 21:00:35 +0000 (GMT) Received: from nalasex01b.na.qualcomm.com (nalasex01b.na.qualcomm.com [10.47.209.197]) by NALASPPMTA01.qualcomm.com (8.18.1.2/8.18.1.2) with ESMTPS id 533L0ZRD032394 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 3 Apr 2025 21:00:35 GMT Received: from [10.110.110.182] (10.80.80.8) by nalasex01b.na.qualcomm.com (10.47.209.197) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Thu, 3 Apr 2025 14:00:34 -0700 Message-ID: Date: Thu, 3 Apr 2025 14:00:33 -0700 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v36 22/31] ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp To: Stephan Gerhold CC: , , , , , , , , , , , , , , , , , , , , , Luca Weiss References: <871827f0-94ba-4565-865f-775cab9501eb@quicinc.com> <200c08f7-3637-c2fb-2caa-002604b957ed@quicinc.com> <378af3f1-b5b0-4f7a-ab62-f5c891feb7b5@quicinc.com> <7d5fd3bf-c33e-4274-938b-2fb93c4b39d8@quicinc.com> Content-Language: en-US From: Wesley Cheng In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01b.na.qualcomm.com (10.47.209.197) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: npZwLy4X00mIJ7RH5NbZ7QPK_DAas2YR X-Authority-Analysis: v=2.4 cv=XamJzJ55 c=1 sm=1 tr=0 ts=67eef6f3 cx=c_pps a=ouPCqIW2jiPt+lZRy3xVPw==:117 a=ouPCqIW2jiPt+lZRy3xVPw==:17 a=GEpy-HfZoHoA:10 a=IkcTkHD0fZMA:10 a=XR8D0OoHHMoA:10 a=COk6AnOGAAAA:8 a=5dSfeLAkA3Y8wAJoHGcA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=TjNXssC_j7lpFel5tvFf:22 X-Proofpoint-ORIG-GUID: npZwLy4X00mIJ7RH5NbZ7QPK_DAas2YR X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1095,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-04-03_09,2025-04-03_03,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 mlxlogscore=999 suspectscore=0 impostorscore=0 mlxscore=0 bulkscore=0 phishscore=0 lowpriorityscore=0 malwarescore=0 adultscore=0 priorityscore=1501 clxscore=1015 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2502280000 definitions=main-2504030111 On 4/3/2025 11:00 AM, Stephan Gerhold wrote: > On Thu, Apr 03, 2025 at 08:58:11AM -0700, Wesley Cheng wrote: >> On 4/3/2025 6:45 AM, Stephan Gerhold wrote: >>> On Wed, Apr 02, 2025 at 05:54:45PM -0700, Wesley Cheng wrote: >>>> On 4/2/2025 5:23 PM, Wesley Cheng wrote: >>>>> On 4/2/2025 7:41 AM, Stephan Gerhold wrote: >>>>>> On Tue, Apr 01, 2025 at 04:47:41PM -0700, Wesley Cheng wrote: >>>>>>> On 4/1/2025 1:16 AM, Stephan Gerhold wrote: >>>>>>>> On Mon, Mar 31, 2025 at 12:52:19PM -0700, Wesley Cheng wrote: >>>>>>>>> On 3/26/2025 2:57 AM, Stephan Gerhold wrote: >>>>>>>>>> On Tue, Mar 25, 2025 at 04:18:03PM -0700, Wesley Cheng wrote: >>>>>>>>>>> On 3/25/2025 2:24 AM, Stephan Gerhold wrote: >>>>>>>>>>>> On Tue, Mar 18, 2025 at 05:51:32PM -0700, Wesley Cheng wrote: >>>>>>>>>>>>> The QC ADSP is able to support USB >>>>>>>>>>>>> playback endpoints, so that the main >>>>>>>>>>>>> application processor can be placed into >>>>>>>>>>>>> lower CPU power modes.  This adds >>>>>>>>>>>>> the required AFE port configurations and >>>>>>>>>>>>> port start command to start an >>>>>>>>>>>>> audio session. >>>>>>>>>>>>> >>>>>>>>>>>>> Specifically, the QC ADSP can support >>>>>>>>>>>>> all potential endpoints that are >>>>>>>>>>>>> exposed by the audio data interface.  >>>>>>>>>>>>> This includes isochronous data >>>>>>>>>>>>> endpoints, in either synchronous mode or >>>>>>>>>>>>> asynchronous mode. In the latter >>>>>>>>>>>>> case both implicit or explicit feedback >>>>>>>>>>>>> endpoints are supported.  The size >>>>>>>>>>>>> of audio samples sent per USB frame >>>>>>>>>>>>> (microframe) will be adjusted based on >>>>>>>>>>>>> information received on the feedback endpoint. >>>>>>>>>>>>> >>>>>>>>>>>>> Some pre-requisites are needed before >>>>>>>>>>>>> issuing the AFE port start command, >>>>>>>>>>>>> such as setting the USB AFE dev_token.  >>>>>>>>>>>>> This carries information about the >>>>>>>>>>>>> available USB SND cards and PCM devices >>>>>>>>>>>>> that have been discovered on the >>>>>>>>>>>>> USB bus.  The dev_token field is used by >>>>>>>>>>>>> the audio DSP to notify the USB >>>>>>>>>>>>> offload driver of which card and PCM index to enable playback on. >>>>>>>>>>>>> >>>>>>>>>>>>> Signed-off-by: Wesley Cheng >>>>>>>>>>>>> --- >>>>>>>>>>>>>   sound/soc/qcom/qdsp6/q6afe-dai.c         |  60 +++++++ >>>>>>>>>>>>>   >>>>>>>>>>>>> sound/soc/qcom/qdsp6/q6afe.c             >>>>>>>>>>>>> | 192 ++++++++++++++++++++++- >>>>>>>>>>>>>   sound/soc/qcom/qdsp6/q6afe.h             |  36 ++++- >>>>>>>>>>>>>   sound/soc/qcom/qdsp6/q6dsp-lpass-ports.c |  23 +++ >>>>>>>>>>>>>   sound/soc/qcom/qdsp6/q6dsp-lpass-ports.h |   1 + >>>>>>>>>>>>>   sound/soc/qcom/qdsp6/q6routing.c         |  32 +++- >>>>>>>>>>>>>   6 files changed, 341 insertions(+), 3 deletions(-) >>>>>>>>>>>>> >>>>>>>>>>> [...] >>>>>>>>>>>>> diff --git >>>>>>>>>>>>> a/sound/soc/qcom/qdsp6/q6routing.c >>>>>>>>>>>>> b/sound/soc/qcom/qdsp6/q6routing.c >>>>>>>>>>>>> index 90228699ba7d..b7439420b425 100644 >>>>>>>>>>>>> --- a/sound/soc/qcom/qdsp6/q6routing.c >>>>>>>>>>>>> +++ b/sound/soc/qcom/qdsp6/q6routing.c >>>>>>>>>>>>> @@ -435,6 +435,26 @@ static struct >>>>>>>>>>>>> session_data *get_session_from_id(struct >>>>>>>>>>>>> msm_routing_data *data, >>>>>>>>>>>>>       return NULL; >>>>>>>>>>>>>   } >>>>>>>>>>>>> + >>>>>>>>>>>>> +static bool is_usb_routing_enabled(struct msm_routing_data *data) >>>>>>>>>>>>> +{ >>>>>>>>>>>>> +    int i; >>>>>>>>>>>>> + >>>>>>>>>>>>> +    /* >>>>>>>>>>>>> +     * Loop through current sessions to >>>>>>>>>>>>> see if there are active routes >>>>>>>>>>>>> +     * to the USB_RX backend DAI.  The >>>>>>>>>>>>> USB offload routing is designed >>>>>>>>>>>>> +     * similarly to the non offload >>>>>>>>>>>>> path.  If there are multiple PCM >>>>>>>>>>>>> +     * devices associated with the ASoC >>>>>>>>>>>>> platform card, only one active >>>>>>>>>>>>> +     * path can be routed to the USB offloaded endpoint. >>>>>>>>>>>>> +     */ >>>>>>>>>>>>> +    for (i = 0; i < MAX_SESSIONS; i++) { >>>>>>>>>>>>> +        if (data->sessions[i].port_id == USB_RX) >>>>>>>>>>>>> +            return true; >>>>>>>>>>>>> +    } >>>>>>>>>>>>> + >>>>>>>>>>>>> +    return false; >>>>>>>>>>>>> +} >>>>>>>>>>>> >>>>>>>>>>>> What is different about USB_RX compared to >>>>>>>>>>>> other output ports we have in >>>>>>>>>>>> Q6AFE? Obviously, we can only play one >>>>>>>>>>>> stream on an output port. But >>>>>>>>>>>> doesn't the ADSP mix streams together when >>>>>>>>>>>> you have multiple routes? >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> This patch will limit the USB_RX from being able >>>>>>>>>>> to be mixed to multiple >>>>>>>>>>> q6adm paths. >>>>>>>>>>> >>>>>>>>>>>> Also, this doesn't actually check for *active* routes only. It just >>>>>>>>>>>> looks if any other MultiMedia DAI is >>>>>>>>>>>> configured to output to USB_RX. >>>>>>>>>>>> That doesn't mean they will ever be active at the same time. >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Yes, the main reason being that that is the >>>>>>>>>>> mechanism we use to populate >>>>>>>>>>> the active offload path within the USB SND card mixer. >>>>>>>>>>> >>>>>>>>>>>> I might for example want to have MultiMedia1 and MultiMedia2 both >>>>>>>>>>>> configured to output to USB_RX. Let's assume >>>>>>>>>>>> MultiMedia1 is a normal PCM >>>>>>>>>>>> DAI, MultiMedia2 is a compress offload DAI. When I want to playback >>>>>>>>>>>> normal audio, I go through MultiMedia1, when >>>>>>>>>>>> I want to play compressed >>>>>>>>>>>> audio, I go through MultiMedia2. Only one of them active at a time. >>>>>>>>>>>> Why can't I set this up statically in the mixers? >>>>>>>>>>>> >>>>>>>>>>>> If you confirm that it is really impossible >>>>>>>>>>>> to have multiple streams >>>>>>>>>>>> mixed together to the USB_RX output in the >>>>>>>>>>>> ADSP, then this should be a >>>>>>>>>>>> runtime check instead when starting the stream IMO. >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> We can have multiple streams being mixed together, but it will get >>>>>>>>>>> confusing because it changes the definition that >>>>>>>>>>> we had discussed about in >>>>>>>>>>> the past about the overall design for the interaction w/ userspace. >>>>>>>>>>> Although we (QC) only support a single USB audio >>>>>>>>>>> device for offloading, >>>>>>>>>>> there could be other situations where the audio >>>>>>>>>>> DSP can support multiple >>>>>>>>>>> devices.  The assumption is that each MM path is >>>>>>>>>>> assigned to a USB device. >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> Are you referring to the "USB Offload Playback Route >>>>>>>>>> PCM#*" mixers here? >>>>>>>>>> They could just refer to first of the configured MM paths, if someone >>>>>>>>>> decides to route multiple paths to the USB backend. Looking at >>>>>>>>>> q6usb_update_offload_route(), I think the implementation does that >>>>>>>>>> already. >>>>>>>>>> >>>>>>>>>> I think it's fine that the userspace API for >>>>>>>>>> automatically "probing" the >>>>>>>>>> PCM device supports only a single path to the USB backend. But if >>>>>>>>>> someone wants to bypass the automatic probing and configure a more >>>>>>>>>> advanced setup, do we need to forbid that? >>>>>>>>>> >>>>>>>>>> Asked differently: what would happen if we remove this check here and >>>>>>>>>> handle USB_RX like any other Q6AFE output port? >>>>>>>>>> Would anything break for >>>>>>>>>> the userspace interface? >>>>>>>>>> >>>>>>>>> >>>>>>>>> So I took a look at seeing how the Q6ADM/ASM >>>>>>>>> interactions would work for >>>>>>>>> the situation where if user tried to start both MM1/2 >>>>>>>>> streams at the same >>>>>>>>> time over the USB offload path.  In this scenario, we >>>>>>>>> see that the Q6USB BE >>>>>>>>> DAI operations, ie startup, hw_params, etc... gets >>>>>>>>> called one time for the >>>>>>>>> initial stream.  For example, if I start playback on MM1, then that >>>>>>>>> triggers the USB BE DAI to be brought up. >>>>>>>>> >>>>>>>>> When I start playback on MM2, since MM1 already called >>>>>>>>> dpcm_be_dai_startup(), then be->dpcm[stream].users will >>>>>>>>> be greater than >>>>>>>>> zero.  This would cause the __soc_pcm_open() to be >>>>>>>>> skipped for the USB BE >>>>>>>>> DAI, so I wouldn't be able to check the runtime status >>>>>>>>> at the Q6USB backend >>>>>>>>> DAI.  However, we do track current streaming sessions >>>>>>>>> done over Q6 ADM and >>>>>>>>> it does save the AFE port associated to each COPP >>>>>>>>> allocation, so I think its >>>>>>>>> reasonable to see if there is already a COPP entry for >>>>>>>>> the USB AFE port, to >>>>>>>>> fail the open() call associated to the FE DAI. >>>>>>>>> >>>>>>>> >>>>>>>> This sounds like a reasonable approach *if* we have to prevent multiple >>>>>>>> MM DAIs from streaming to the USB AFE port at the same time. >>>>>>>> >>>>>>>> It's still unclear to me why we have to introduce this >>>>>>>> limitation in the >>>>>>>> first place. I think the questions from my previous email are still >>>>>>>> open. Can you check them again? >>>>>>>> >>>>>>> >>>>>>> So I checked with our audio DSP folks, and they mentioned there isn't >>>>>>> technically a limitation from mixing multiple ADM streams from >>>>>>> their end. >>>>>>> My observations are as follows: >>>>>>> - Using tinyplay to open and play on different FE PCM devices >>>>>>> (ie MM1 and >>>>>>> MM2), both streams are audible on the USB headset (intermixed). >>>>>>> - If starting playback on MM1 first, before MM2, then once playback is >>>>>>> complete on MM1, the ADM close is also affecting the MM2 stream. >>>>>>> Basically, MM2 stops when the MM1 audio file is completed. >>>>>>> - Due to the abrupt/incomplete closing of the MM2 ADM stream, looks like >>>>>>> the audio DSP is not handling that case well, so subsequent >>>>>>> playbacks fail. >>>>>>> >>>>>> >>>>>> Thanks a lot for testing this! >>>>>> >>>>>>> I did find a possible reason for this, and it seems to be due to >>>>>>> some code >>>>>>> unrelated to the USB offload path directly.  It looks like the Q6ADM is >>>>>>> currently built in a way that you can only route streams to a single >>>>>>> endpoint, even though we do have reference counting for each >>>>>>> COPP profile. >>>>>>> So even after the first MM1 ADM stream completes and the PCM device is >>>>>>> closed, the MM1 ADM close callback will issue a q6adm_device_close() for >>>>>>> the USB AFE port. >>>>>> >>>>>> Yeah, this sounds like a bug to me... >>>>>> >>>>>>> >>>>>>> I made some test changes to account for the refcount before issuing the >>>>>>> q6adm_device_close(), and that seemed to work.  Once the MM1 >>>>>>> stream closes, >>>>>>> it allows for the MM2 stream to close/finish before issuing the command, >>>>>>> and that allows for proper cleanup of the audio data. >>>>>>> >>>>>>> IMO, I would like to keep the initial behavior (ie, blocking the >>>>>>> additional >>>>>>> stream open from the kernel) until I can get some more testing done, and >>>>>>> figure out if this is the correct approach.  If it is, I can submit a >>>>>>> follow up series to address it. >>>>>>> >>>>>> >>>>>> I'm fine with this approach. My only two concerns/comments are: >>>>>> >>>>>>   1. Let's make sure we don't waste too much time finding the ideal >>>>>>      approach to implement the additional blocking, if this will likely >>>>>>      end up getting removed again anyway. >>>>>> >>>>>>   2. How can we justify making this change only for USB? Your analysis >>>>>>      sounds like the issue applies to all types of output ports. This was >>>>>>      exactly my main concern with the check you added in this patch: >>>>>>      I would expect QDSP6 treats all ports exactly the same. This means >>>>>>      we should add this additional check for all the output ports... >>>>>> >>>>> >>>>> Fair points...I will extend this check across all ports until I get back >>>>> with seeing how we can address the mixing situation. >>>>> >>>> >>>> Sorry for replying again. I think I'll at least limit this to the playback >>>> path only for now. I'm not sure how the behavior yet is for the record >>>> path, since I don't really have that use case to test with yet :). I will >>>> see how it looks like when the record USB offload is done. >>>> >>> >>> FWIW, I tested this on MSM8916: >>> >>> - MultiMedia1 -> PRI_MI2S_RX >>> - MultiMedia3 -> PRI_MI2S_RX >>> - TERT_MI2S_TX -> MultiMedia2 >>> - TERT_MI2S_TX -> MultiMedia5 >>> >>> 2x speaker-test to MultiMedia1 and MultiMedia3 (pink noise + sine wave): >>> -> Audio playback correctly mixed together >>> -> Playback aborts for both when stopping one of the processes >>> Write error: -5,I/O error >>> xrun_recovery failed: -5,I/O error >>> Transfer failed: I/O error >>> -> Kernel log: >>> [ 585.679421] q6routing 4080000.remoteproc:smd-edge:apr:service@8:routing: Found Matching Copp 0x0 >>> [ 587.917135] qcom-q6adm aprsvc:service:4:8: cmd = 0x10327 return error = 0x2 >>> [ 587.917378] qcom-q6adm aprsvc:service:4:8: DSP returned error[2] >>> [ 587.917409] qcom-q6adm aprsvc:service:4:8: Failed to close copp -22 >>> >>> 2x arecord from MultiMedia2 and MultiMedia5: >>> -> Both processes record audio as expected >>> -> Recording aborts for both when stopping one of the processes >>> arecord: pcm_read:2272: read error: I/O error >>> -> Kernel log: >>> [ 646.125612] q6routing 4080000.remoteproc:smd-edge:apr:service@8:routing: Found Matching Copp 0x0 >>> [ 654.247867] q6asm-dai 4080000.remoteproc:smd-edge:apr:service@7:dais: command[0x10bdb] not expecting rsp >>> [ 654.815474] q6asm-dai 4080000.remoteproc:smd-edge:apr:service@7:dais: command[0x10bdb] not expecting rsp >>> [ 654.825568] qcom-q6adm aprsvc:service:4:8: cmd = 0x10327 return error = 0x2 >>> [ 654.825955] qcom-q6adm aprsvc:service:4:8: DSP returned error[2] >>> [ 654.826013] qcom-q6adm aprsvc:service:4:8: Failed to close copp -22 >>> >>> => Both playback and recording are affected. As you suspected it's >>> unrelated to USB. >>> >> >> Great, thanks for confirming both paths show the same issue :). >> >>> This feels like a bug to me rather than an intentional limitation. If >>> you can share the fix you made I can test it here. >>> >> >> Change I tried was fairly straightforward. Sharing it below: >> >> diff --git a/sound/soc/qcom/qdsp6/q6adm.c b/sound/soc/qcom/qdsp6/q6adm.c >> index fe719c4c32b3..7880fbbe815f 100644 >> --- a/sound/soc/qcom/qdsp6/q6adm.c >> +++ b/sound/soc/qcom/qdsp6/q6adm.c >> @@ -578,12 +579,13 @@ int q6adm_close(struct device *dev, struct q6copp *copp) >> struct q6adm *adm = dev_get_drvdata(dev->parent); >> int ret = 0; >> >> - ret = q6adm_device_close(adm, copp, copp->afe_port, copp->copp_idx); >> - if (ret < 0) { >> - dev_err(adm->dev, "Failed to close copp %d\n", ret); >> - return ret; >> + if (kref_read(&copp->refcount) == 1) { >> + ret = q6adm_device_close(adm, copp, copp->afe_port, copp->copp_idx); >> + if (ret < 0) { >> + dev_err(adm->dev, "Failed to close copp %d\n", ret); >> + return ret; >> + } >> } >> - >> kref_put(&copp->refcount, q6adm_free_copp); >> >> return 0; >> > > Hmm, yeah it looks like we need some reference counting for the > open/close operation. I think checking the refcount like that is going > to be prone to potential race conditions though. I'm not sure if we can > guarantee that q6adm_close() isn't called concurrently. > Yeah, I was hoping there was some locking in the ASoC levels, but its going to be locking based on the runtime PCM stream, so that wouldn't prevent q6adm_close() running concurrently. (as MM1/2 are different RTDs) > I played around a bit and came up with the two patches below. I think > those should be good. Given the "Found Matching Copp" code path, it > feels like this was the intended behavior all along. I can post these if > you have no objections. You could then just go ahead with your series by > removing the check I originally commented on in this patch. > OK, that sounds good to me. Thanks for helping out with this part of my series. Definitely think its a good idea to have an explicit mutex that is managing the Q6ADM open/close ops. Thanks Wesley Cheng