From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Xu Yang <xu.yang_2@nxp.com>
Cc: ezequiel@vanguardiasur.com.ar, mchehab@kernel.org,
laurent.pinchart@ideasonboard.com, hdegoede@redhat.com,
gregkh@linuxfoundation.org, mingo@kernel.org, tglx@linutronix.de,
viro@zeniv.linux.org.uk, thomas.weissschuh@linutronix.de,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-usb@vger.kernel.org, imx@lists.linux.dev, jun.li@nxp.com
Subject: Re: [PATCH v2 0/3] add dma noncoherent API
Date: Fri, 27 Jun 2025 14:25:41 +0300 [thread overview]
Message-ID: <aF5_td2Bb2vsAJ43@smile.fi.intel.com> (raw)
In-Reply-To: <20250627101939.3649295-1-xu.yang_2@nxp.com>
On Fri, Jun 27, 2025 at 06:19:36PM +0800, Xu Yang wrote:
> On architectures where there is no coherent caching such as ARM it's
> proved that using dma_alloc_noncontiguous API and handling manually
dma_alloc_noncontiguous()
> the cache flushing will significantly improve performance.
> Refer to:
> commit 20e1dbf2bbe2 ("media: uvcvideo: Use dma_alloc_noncontiguous API")
> commit 68d0c3311ec1 ("media: stk1160: use dma_alloc_noncontiguous API")
>
> However, it's obvious that there is significant code duplication between
> these two commits. Beside, a potential user USB Monitor may read outdated
> data before the driver do dma sync for cpu which will make the data
DMA
CPU
> unreliable.
>
> To reduce code duplication and avoid USB Monitor result unreliable, this
> series will introduce dma noncoherent API to usb core. And the USB core
DMA
USB
> layer will manage synchronization itself.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2025-06-27 11:25 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-27 10:19 [PATCH v2 0/3] add dma noncoherent API Xu Yang
2025-06-27 10:19 ` [PATCH v2 1/3] usb: core: add dma-noncoherent buffer alloc and free API Xu Yang
2025-06-27 11:22 ` Andy Shevchenko
2025-06-30 7:26 ` Xu Yang
2025-06-27 14:23 ` Alan Stern
2025-06-29 23:39 ` Laurent Pinchart
2025-06-30 6:48 ` Ricardo Ribalda
2025-06-30 8:23 ` Laurent Pinchart
2025-06-30 13:37 ` Christoph Hellwig
2025-06-30 8:45 ` Xu Yang
2025-06-30 8:18 ` Xu Yang
2025-06-30 14:16 ` Alan Stern
2025-06-30 17:38 ` Laurent Pinchart
2025-07-01 9:32 ` Xu Yang
2025-06-27 10:19 ` [PATCH v2 2/3] media: uvcvideo: use usb_alloc_noncoherent/usb_free_noncoherent() Xu Yang
2025-06-27 10:19 ` [PATCH v2 3/3] media: stk1160: " Xu Yang
2025-06-27 11:25 ` Andy Shevchenko [this message]
2025-06-30 7:28 ` [PATCH v2 0/3] add dma noncoherent API Xu Yang
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