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From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Shih-Yuan Lee <fourdollars@debian.org>
Cc: Mark Brown <broonie@kernel.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Lukas Wunner <lukas@wunner.de>, Daniel Mack <daniel@zonque.org>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v17 5/6] spi: pxa2xx-pci: restore LPSS private register state across S3 resume
Date: Thu, 1 Oct 2026 06:13:01 +0200	[thread overview]
Message-ID: <20261001041301.GC176164@black.igk.intel.com> (raw)
In-Reply-To: <20260930160629.1822-6-fourdollars@debian.org>

Hi,

On Thu, Oct 01, 2026 at 12:06:28AM +0800, Shih-Yuan Lee wrote:
> On platforms where Intel LPSS SPI is enumerated as a bare PCI device
> (such as the Apple MacBook8,1 on Lynxpoint-LP), the LPSS power island
> loses power during system sleep and powers up with the controller held
> in reset. Because the device lacks ACPI companion objects or MFD
> binding, neither drivers/acpi/x86/lpss.c nor drivers/mfd/intel-lpss.c
> restore the private register context across S3 resume.

Hmm, how is that possible? The LPSS is a single PCI device that only the
the LPSS MFD driver binds to. I don't think it is any different in Apple
platforms than any other regular PC platforms in that sense. What does
lspci -vv show on this system?

  reply	other threads:[~2026-10-01  4:13 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-30 16:06 [PATCH v17 0/6] spi: pxa2xx: PM fixes, teardown overhaul, and LPSS restore for MacBook8,1 Shih-Yuan Lee
2026-09-30 16:06 ` [PATCH v17 1/6] spi: pxa2xx: rename local status variable to ret Shih-Yuan Lee
2026-10-01  7:10   ` Andy Shevchenko
2026-09-30 16:06 ` [PATCH v17 2/6] spi: pxa2xx: introduce clock enable and disable helper functions Shih-Yuan Lee
2026-09-30 17:31   ` Mark Brown
2026-10-01  7:13   ` Andy Shevchenko
2026-09-30 16:06 ` [PATCH v17 3/6] spi: pxa2xx: acquire active PM runtime reference in interrupt handler Shih-Yuan Lee
2026-09-30 17:40   ` Mark Brown
2026-09-30 16:06 ` [PATCH v17 4/6] spi: pxa2xx: overhaul teardown and suspend sequence to synchronize IRQ before clock gating Shih-Yuan Lee
2026-09-30 16:06 ` [PATCH v17 5/6] spi: pxa2xx-pci: restore LPSS private register state across S3 resume Shih-Yuan Lee
2026-10-01  4:13   ` Mika Westerberg [this message]
2026-10-01  7:20   ` Andy Shevchenko
2026-09-30 16:06 ` [PATCH v17 6/6] spi: pxa2xx-pci: disable DMA and runtime autosuspend for Apple MacBook8,1 Shih-Yuan Lee

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