4.4-stable review patch. If anyone has any objections, please let me know.
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From: Hans de Goede hdegoede@redhat.com
commit fdcb613d49321b5bf5d5a1bd0fba8e7c241dcc70 upstream.
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 Signed-off-by: Sudip Mukherjee sudipm.mukherjee@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/acpi/acpi_lpss.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/acpi/acpi_lpss.c +++ b/drivers/acpi/acpi_lpss.c @@ -154,10 +154,12 @@ static const struct lpss_device_desc lpt
static const struct lpss_device_desc byt_pwm_dev_desc = { .flags = LPSS_SAVE_CTX, + .prv_offset = 0x800, };
static const struct lpss_device_desc bsw_pwm_dev_desc = { .flags = LPSS_SAVE_CTX | LPSS_NO_D3_DELAY, + .prv_offset = 0x800, };
static const struct lpss_device_desc byt_uart_dev_desc = {