This is a note to let you know that I've just added the patch titled

serdev: Fix detection of UART devices on Apple machines.

to my tty git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git in the tty-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 35d4670aaec7206b5ef19c842ca33076bde562e4 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Ronald=20Tschal=C3=A4r?= ronald@innovation.ch Date: Tue, 11 Feb 2020 11:47:23 -0800 Subject: serdev: Fix detection of UART devices on Apple machines. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

On Apple devices the _CRS method returns an empty resource template, and the resource settings are instead provided by the _DSM method. But commit 33364d63c75d6182fa369cea80315cf1bb0ee38e (serdev: Add ACPI devices by ResourceSource field) changed the search for serdev devices to require valid, non-empty resource template, thereby breaking Apple devices and causing bluetooth devices to not be found.

This expands the check so that if we don't find a valid template, and we're on an Apple machine, then just check for the device being an immediate child of the controller and having a "baud" property.

Cc: stable@vger.kernel.org # 5.5 Fixes: 33364d63c75d ("serdev: Add ACPI devices by ResourceSource field") Signed-off-by: Ronald Tschalär ronald@innovation.ch Link: https://lore.kernel.org/r/20200211194723.486217-1-ronald@innovation.ch Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serdev/core.c | 10 ++++++++++ 1 file changed, 10 insertions(+)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c index 42345e79920c..c5f0d936b003 100644 --- a/drivers/tty/serdev/core.c +++ b/drivers/tty/serdev/core.c @@ -18,6 +18,7 @@ #include <linux/sched.h> #include <linux/serdev.h> #include <linux/slab.h> +#include <linux/platform_data/x86/apple.h>

static bool is_registered; static DEFINE_IDA(ctrl_ida); @@ -631,6 +632,15 @@ static int acpi_serdev_check_resources(struct serdev_controller *ctrl, if (ret) return ret;

+ /* + * Apple machines provide an empty resource template, so on those + * machines just look for immediate children with a "baud" property + * (from the _DSM method) instead. + */ + if (!lookup.controller_handle && x86_apple_machine && + !acpi_dev_get_property(adev, "baud", ACPI_TYPE_BUFFER, NULL)) + acpi_get_parent(adev->handle, &lookup.controller_handle); + /* Make sure controller and ResourceSource handle match */ if (ACPI_HANDLE(ctrl->dev.parent) != lookup.controller_handle) return -ENODEV;