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From: Frank Li <Frank.li@nxp.com>
To: Billy Tsai <billy_tsai@aspeedtech.com>,
	Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Nicolas Pitre <npitre@baylibre.com>,
	Boris Brezillon <boris.brezillon@collabora.com>,
	linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] i3c: mipi-i3c-hci: fix atomic updates to RING_OPERATION1 register
Date: Tue, 31 Mar 2026 10:57:35 -0400	[thread overview]
Message-ID: <acvg36HWslcwTFht@lizhi-Precision-Tower-5810> (raw)
In-Reply-To: <20260331-i3c-hci-dma-lock-v1-1-708bc5848381@aspeedtech.com>

On Tue, Mar 31, 2026 at 08:12:23PM +0800, Billy Tsai wrote:
> The RING_OPERATION1 register contains multiple bitfields (enqueue,
> software dequeue, and IBI dequeue pointers) that are updated from
> different contexts. Because these updates are performed via
> read-modify-write sequences, concurrent access from process and IRQ
> contexts can lead to lost updates.
>
> Example:
> CPU 0 (hci_dma_queue_xfer): reads RING_OPERATION1 (enq=5, deq=2)
> CPU 1 (hci_dma_xfer_done): reads RING_OPERATION1 (enq=5, deq=2)

Add Adrian Hunter <adrian.hunter@intel.com>, who add lock at equeue.

https://lore.kernel.org/linux-i3c/20260306072451.11131-6-adrian.hunter@intel.com/

Dose above patch fix your problem ?

Frank

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  reply	other threads:[~2026-03-31 14:57 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-31 12:12 [PATCH] i3c: mipi-i3c-hci: fix atomic updates to RING_OPERATION1 register Billy Tsai
2026-03-31 14:57 ` Frank Li [this message]
2026-04-01  5:53   ` Billy Tsai
2026-04-01  7:50     ` Adrian Hunter
2026-04-01  8:04       ` Billy Tsai
2026-04-02  7:15         ` Alexandre Belloni
2026-04-02  7:46           ` Billy Tsai

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