The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From fdcb613d49321b5bf5d5a1bd0fba8e7c241dcc70 Mon Sep 17 00:00:00 2001
From: Hans de Goede hdegoede@redhat.com Date: Thu, 26 Apr 2018 14:10:24 +0200 Subject: [PATCH] ACPI / LPSS: Add missing prv_offset setting for byt/cht PWM devices
The LPSS PWM device on on Bay Trail and Cherry Trail devices has a set of private registers at offset 0x800, the current lpss_device_desc for them already sets the LPSS_SAVE_CTX flag to have these saved/restored over device-suspend, but the current lpss_device_desc was not setting the prv_offset field, leading to the regular device registers getting saved/restored instead.
This is causing the PWM controller to no longer work, resulting in a black screen, after a suspend/resume on systems where the firmware clears the APB clock and reset bits at offset 0x804.
This commit fixes this by properly setting prv_offset to 0x800 for the PWM devices.
Cc: stable@vger.kernel.org Fixes: e1c748179754 ("ACPI / LPSS: Add Intel BayTrail ACPI mode PWM") Fixes: 1bfbd8eb8a7f ("ACPI / LPSS: Add ACPI IDs for Intel Braswell") Signed-off-by: Hans de Goede hdegoede@redhat.com Acked-by: Rafael J . Wysocki rjw@rjwysocki.net Signed-off-by: Thierry Reding thierry.reding@gmail.com
diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c index 2bcffec8dbf0..c4ba9164e582 100644 --- a/drivers/acpi/acpi_lpss.c +++ b/drivers/acpi/acpi_lpss.c @@ -229,11 +229,13 @@ static const struct lpss_device_desc lpt_sdio_dev_desc = {
static const struct lpss_device_desc byt_pwm_dev_desc = { .flags = LPSS_SAVE_CTX, + .prv_offset = 0x800, .setup = byt_pwm_setup, };
static const struct lpss_device_desc bsw_pwm_dev_desc = { .flags = LPSS_SAVE_CTX | LPSS_NO_D3_DELAY, + .prv_offset = 0x800, .setup = bsw_pwm_setup, };