From: Wesley Cheng <quic_wcheng@quicinc.com>
To: Mathias Nyman <mathias.nyman@linux.intel.com>,
<srinivas.kandagatla@linaro.org>, <mathias.nyman@intel.com>,
<perex@perex.cz>, <conor+dt@kernel.org>, <corbet@lwn.net>,
<lgirdwood@gmail.com>, <andersson@kernel.org>,
<krzysztof.kozlowski+dt@linaro.org>, <gregkh@linuxfoundation.org>,
<Thinh.Nguyen@synopsys.com>, <broonie@kernel.org>,
<bgoswami@quicinc.com>, <tiwai@suse.com>, <robh@kernel.org>,
<konrad.dybcio@linaro.org>
Cc: <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-sound@vger.kernel.org>, <linux-usb@vger.kernel.org>,
<linux-arm-msm@vger.kernel.org>, <linux-doc@vger.kernel.org>,
<alsa-devel@alsa-project.org>
Subject: Re: [PATCH v20 03/41] usb: host: xhci: Repurpose event handler for skipping interrupter events
Date: Tue, 30 Apr 2024 14:57:28 -0700 [thread overview]
Message-ID: <33dfa0c5-c43f-79f6-2700-beee2e5d389f@quicinc.com> (raw)
In-Reply-To: <12d29c54-c005-7112-0933-d9d28f11abd6@linux.intel.com>
Hi Mathias,
On 4/30/2024 4:02 AM, Mathias Nyman wrote:
> On 26.4.2024 0.50, Wesley Cheng wrote:
>> Depending on the interrupter use case, the OS may only be used to handle
>> the interrupter event ring clean up. In these scenarios, event TRBs
>> don't
>> need to be handled by the OS, so introduce an xhci interrupter flag to
>> tag
>> if the events from an interrupter needs to be handled or not.
>
> Could you elaborate on this a bit.
>
> If I understood correctly the whole point of requesting a secondary xhci
> interrupter
> for the sideband device without ever requesting a real interrupt for it
> was to avoid
> waking up the cpu and calling the interrupt handler.
>
Yes, this is the correct understanding. We don't currently register the
separate interrupt line (from GIC) for the secondary interrupter, so the
main apps proc doesn't get interrupted on events generated on the
secondary interrupter.
> with this flag is seems the normal xhci interrupt handler does get
> called for
> sideband transfer events.
>
Main intention was to utilize the refactoring you did to expose the
xhci_handle_event_trb() for both handling events on the main
interrupter, as well as the logic to skip events on the secondary
interrupter.
https://lore.kernel.org/linux-usb/44a3d4db-7759-dd93-782a-1efbebfdb22c@linux.intel.com/
>>
>> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
>> ---
>> drivers/usb/host/xhci-ring.c | 17 +++++++++++++----
>> drivers/usb/host/xhci.h | 1 +
>> 2 files changed, 14 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
>> index 52278afea94b..6c7a21f522cd 100644
>> --- a/drivers/usb/host/xhci-ring.c
>> +++ b/drivers/usb/host/xhci-ring.c
>> @@ -2973,14 +2973,22 @@ static int handle_tx_event(struct xhci_hcd *xhci,
>> }
>> /*
>> - * This function handles one OS-owned event on the event ring. It may
>> drop
>> - * xhci->lock between event processing (e.g. to pass up port status
>> changes).
>> + * This function handles one OS-owned event on the event ring, or
>> ignores one event
>> + * on interrupters which are non-OS owned. It may drop xhci->lock
>> between event
>> + * processing (e.g. to pass up port status changes).
>> */
>> static int xhci_handle_event_trb(struct xhci_hcd *xhci, struct
>> xhci_interrupter *ir,
>> union xhci_trb *event)
>> {
>> u32 trb_type;
>> + /*
>> + * Some interrupters do not need to handle event TRBs, as they
>> may be
>> + * managed by another entity, but rely on the OS to clean up.
>> + */
>> + if (ir->skip_events)
>> + return 0;
>> +
>
> I think we need another solution than a skip_events flag.
>
> To make secondary xhci interrupters more useful in general it would make
> more
> sense to add an interrupt handler function pointer to struct
> xhci_interrupter.
>
> Then call that function instead of xhci_handle_event_trb()
>
I agree that is how it should be for when support for actually utilizing
secondary interrupters for routing events to different targets (instead
of offloading). However, since I don't have an existing use case that
will exercise this functionality, its a bit difficult to verify that it
should be working the way it was intended.
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -3098,8 +3098,8 @@ static int xhci_handle_events(struct xhci_hcd
> *xhci, struct xhci_interrupter *ir
>
> /* Process all OS owned event TRBs on this event ring */
> while (unhandled_event_trb(ir->event_ring)) {
> - err = xhci_handle_event_trb(xhci, ir,
> ir->event_ring->dequeue);
> -
> + if (ir->handle_event_trb)
> + err = ir->handle_event_trb(xhci, ir,
> ir->event_ring->dequeue);
> /*
> * If half a segment of events have been handled in one
> go then
> * update ERDP, and force isoc trbs to interrupt more
> often
>
> The handler function would be passed to, and function pointer set in
> xhci_create_secondary_interrupter()
>
> For primary interrupter it would always be set to xhci_handle_event_trb()
>
Yes, definitely agree with this for when we introduce support for
handling the secondary interrupter GIC line within the apps proc itself.
Would prefer if we took up that effort in another series, but willing
to go back to the skip events loop previously implemented if the above
change isn't where you want to go with this.
Thanks
Wesley Cheng
> Thanks
> Mathias
>
next prev parent reply other threads:[~2024-04-30 21:57 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-25 21:50 [PATCH v20 00/41] Introduce QC USB SND audio offloading support Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 01/41] xhci: add helper to stop endpoint and wait for completion Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 02/41] usb: host: xhci: Export enable and disable interrupter APIs Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 03/41] usb: host: xhci: Repurpose event handler for skipping interrupter events Wesley Cheng
2024-04-30 11:02 ` Mathias Nyman
2024-04-30 21:57 ` Wesley Cheng [this message]
2024-04-25 21:50 ` [PATCH v20 04/41] xhci: export XHCI IMOD setting helper for interrupters Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 05/41] xhci: sideband: add initial api to register a sideband entity Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 06/41] usb: host: xhci-sideband: Expose a sideband interrupter enable API Wesley Cheng
2024-05-02 11:07 ` Mathias Nyman
2024-05-02 23:37 ` Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 07/41] usb: host: xhci-mem: Cleanup pending secondary event ring events Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 08/41] usb: host: xhci-mem: Allow for interrupter clients to choose specific index Wesley Cheng
2024-04-26 13:24 ` Amadeusz Sławiński
2024-04-26 20:03 ` Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 09/41] ASoC: Add SOC USB APIs for adding an USB backend Wesley Cheng
2024-04-26 13:25 ` Amadeusz Sławiński
2024-04-26 21:55 ` Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 10/41] ASoC: dt-bindings: qcom,q6dsp-lpass-ports: Add USB_RX port Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 11/41] ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 12/41] ASoC: qdsp6: q6afe: Increase APR timeout Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 13/41] ASoC: qcom: qdsp6: Add USB backend ASoC driver for Q6 Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 14/41] ALSA: usb-audio: Introduce USB SND platform op callbacks Wesley Cheng
2024-04-25 21:50 ` [PATCH v20 15/41] ALSA: usb-audio: Export USB SND APIs for modules Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 16/41] ALSA: usb-audio: Save UAC sample size information Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 17/41] usb: dwc3: Specify maximum number of XHCI interrupters Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 18/41] usb: host: xhci-plat: Set XHCI max interrupters if property is present Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 19/41] ALSA: usb-audio: qcom: Add USB QMI definitions Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 20/41] ALSA: usb-audio: qcom: Introduce QC USB SND offloading support Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 21/41] ALSA: usb-audio: Check for support for requested audio format Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 22/41] ASoC: usb: Add PCM format check API for USB backend Wesley Cheng
2024-04-26 13:25 ` Amadeusz Sławiński
2024-04-30 8:01 ` Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 23/41] ASoC: qcom: qdsp6: Ensure PCM format is supported by USB audio device Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 24/41] ALSA: usb-audio: Prevent starting of audio stream if in use Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 25/41] ALSA: usb-audio: Do not allow USB offload path if PCM device is " Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 26/41] ASoC: dt-bindings: Update example for enabling USB offload on SM8250 Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 27/41] ALSA: usb-audio: qcom: Populate PCM and USB chip information Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 28/41] ASoC: qcom: qdsp6: Add support to track available USB PCM devices Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 29/41] ASoC: Introduce SND kcontrols to select sound card and PCM device Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 30/41] ASoC: qcom: qdsp6: Add SOC USB offload select get/put callbacks Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 31/41] ASoC: Introduce SND kcontrols to track USB offloading state Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 32/41] ASoC: qcom: qdsp6: Add PCM ops to track current state Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 33/41] ASoC: usb: Create SOC USB SND jack kcontrol Wesley Cheng
2024-04-26 13:26 ` Amadeusz Sławiński
2024-05-01 0:32 ` Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 34/41] ASoC: qcom: qdsp6: Add headphone jack for offload connection status Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 35/41] ASoC: usb: Fetch ASoC sound card information Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 36/41] ALSA: usb-audio: Add USB offloading capable kcontrol Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 37/41] ALSA: usb-audio: Allow for rediscovery of connected USB SND devices Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 38/41] ALSA: usb-audio: qcom: Use card and PCM index from QMI request Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 39/41] ASoC: usb: Rediscover USB SND devices on USB port add Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 40/41] ASoC: qcom: Populate SoC components string Wesley Cheng
2024-04-25 21:51 ` [PATCH v20 41/41] ASoC: doc: Add documentation for SOC USB Wesley Cheng
2024-04-26 3:36 ` Bagas Sanjaya
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