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Date: Tue, 21 Jul 2026 11:00:46 +0200
From: Lukas Wunner <lukas@wunner.de>
To: Shih-Yuan Lee <fourdollars@debian.org>
Cc: Mark Brown <broonie@kernel.org>,
	Andy Shevchenko <andriy.shevchenko@intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Daniel Mack <daniel@zonque.org>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v16 5/7] spi: pxa2xx: disable DMA for Apple MacBook8,1
Message-ID: <al81PmK1UMr2g8p-@wunner.de>
References: <20260720162117.32304-1-fourdollars@debian.org>
 <20260720162117.32304-6-fourdollars@debian.org>
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In-Reply-To: <20260720162117.32304-6-fourdollars@debian.org>

On Tue, Jul 21, 2026 at 12:21:14AM +0800, Shih-Yuan Lee wrote:
> On MacBook8,1 (early 2015 12" MacBook), the LPSS SPI controller at
> 00:15.4 suffers from hardware DMA handshake failures and interrupt
> routing bugs, causing keyboard/touchpad transactions to fail when
> DMA is enabled.
[...]
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=108331

In the bugzilla comments, Leif Liddy writes:

   "I needed to modify drivers/dma/dw/pci.c to assign the DMA controller
    irq value to 21 (which is what is listed in the ACPI table) for it
    to work. The DMA controller was being assigned an irq value of 20
    for some reason."

It would seem better to fix up the incorrect interrupt number in a quirk,
rather than disabling DMA wholesale.

Thanks,

Lukas