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From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: stable@vger.kernel.org
Cc: Hans de Goede <hdegoede@redhat.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Benjamin Tissoires <btissoir@redhat.com>
Subject: Revert f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip") from stable trees
Date: Thu, 26 Apr 2018 15:53:02 +0300	[thread overview]
Message-ID: <20180426125302.GF2173@lahna.fi.intel.com> (raw)

Hi,

It seems that commit f5a26acf0162 ("pinctrl: intel: Initialize GPIO
properly when used through irqchip") can cause problems on some Skylake
systems with Sunrisepoint PCH-H. Namely on certain systems it may turn
the backlight PWM pin from native mode to GPIO which makes the screen
blank during boot.

There is more information here:

  https://bugzilla.redhat.com/show_bug.cgi?id=1543769

The actual reason is that GPIO numbering used in BIOS is using "Windows"
numbers meaning that they don't match the hardware 1:1 and because of
this a wrong pin (backlight PWM) is picked and switched to GPIO mode.

There is a proper fix for this but since it has quite many dependencies
on commits that cannot be considered stable material, I suggest we
revert commit f5a26acf0162 from stable trees 4.9, 4.14 and 4.15 to
prevent the backlight issue.

Thanks!

             reply	other threads:[~2018-04-26 12:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-26 12:53 Mika Westerberg [this message]
2018-04-26 13:24 ` Revert f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip") from stable trees Greg KH
2018-04-26 13:36   ` Mika Westerberg
2018-04-26 15:32     ` Greg KH

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