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List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Nicholas Johnson , linux-sound@vger.kernel.org, Jaroslav Kysela , Takashi Iwai Cc: LKML , linux-doc@vger.kernel.org, Jonathan Corbet , Shuah Khan References: <20260820083646.11383-2-nicholas.johnson-opensource@outlook.com.au> Subject: Re: [RFC PATCH] ALSA: pci: add PreSonus Quantum PCI driver Content-Language: en-GB, de-DE From: Markus Elfring In-Reply-To: <20260820083646.11383-2-nicholas.johnson-opensource@outlook.com.au> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:T1lJN9not0DNdryyKdR7VXbvkYEah/wgGQl6nvofbSm41S0kPp3 94gWR5g60FKfQeCm9Gg2e8axhVANBLveK1Y++wqZDq9CzYeH2shzUhY3fNnp1FvGmzfYiaL sNh8GELpzbQKAA3Wqsw2ywUhTMzmbGKYgtB4nmc8fADBpJMHVOiEPf6N0JUcGXY8NpPXwed 1ylJepnC9XeCCkqnCrH5w== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:rfyKUZjm/tI=;YK/iSZvYOIUMvDrvBhaYSUDH21B UPDguoGKnr0D9LtEqlUfMMenrGdFGpjI1erZQpCaV87ADCWd06+gN8mTp9FvCpHuWkkB+Iugk 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vINRyzfyMOVROxRz94j9dqy9RWIli8techdMHtCDwkmobn6wxWTYy2exejXAIVQ== =E2=80=A6 > +++ b/sound/pci/quantum/quantum_dma.c > @@ -0,0 +1,853 @@ =E2=80=A6 > +static ssize_t cpu_latency_us_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ =E2=80=A6 > + mutex_lock(&chip->dma_mutex); > + chip->cpu_latency_us =3D value; > + if (READ_ONCE(chip->stream_active)) > + quantum_cpu_latency_qos_apply(chip); > + mutex_unlock(&chip->dma_mutex); > + > + return count; > +} =E2=80=A6 Under which circumstances would you become interested to apply a statement like =E2=80=9Cguard(mutex)(&chip->dma_mutex);=E2=80=9D? https://elixir.bootlin.com/linux/v7.2/source/include/linux/mutex.h#L253 Regards, Markus