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From: Hans de Goede <hdegoede@redhat.com>
To: "Thierry Reding" <thierry.reding@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
	"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	"Len Brown" <lenb@kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>,
	linux-pwm@vger.kernel.org,
	intel-gfx <intel-gfx@lists.freedesktop.org>,
	dri-devel@lists.freedesktop.org,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	linux-acpi@vger.kernel.org,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Subject: [PATCH v5 01/16] ACPI / LPSS: Resume Cherry Trail PWM controller in no-irq phase
Date: Fri, 17 Jul 2020 15:37:38 +0200
Message-ID: <20200717133753.127282-2-hdegoede@redhat.com> (raw)
In-Reply-To: <20200717133753.127282-1-hdegoede@redhat.com>

The DSDTs on most Cherry Trail devices have an ugly clutch where the PWM
controller gets poked from the _PS0 method of the graphics-card device:

	Local0 = PSAT /* \_SB_.PCI0.GFX0.PSAT */
	If (((Local0 & 0x03) == 0x03))
	{
	    PSAT &= 0xFFFFFFFC
	    Local1 = PSAT /* \_SB_.PCI0.GFX0.PSAT */
	    RSTA = Zero
	    RSTF = Zero
	    RSTA = One
	    RSTF = One
	    PWMB |= 0xC0000000
	    PWMC = PWMB /* \_SB_.PCI0.GFX0.PWMB */
	}

Where PSAT is the power-status register of the PWM controller, so if it
is in D3 when the GFX0 device's PS0 method runs then it will turn it on
and restore the PWM ctrl register value it saved from its PS3 handler.
Note not only does it restore it, it ors it with 0xC0000000 turning it
on at a time where we may not want it to get turned on at all.

The pwm_get call which the i915 driver does to get a reference to the
PWM controller, already adds a device-link making the GFX0 device a
consumer of the PWM device. So it should already have been resumed when
the above AML runs and the AML should thus not do its undesirable poking
of the PWM controller register.

But the PCI core powers on PCI devices in the no-irq resume phase and
thus calls the troublesome PS0 method in the no-irq resume phase.
Where as LPSS devices by default are resumed in the early resume phase.

This commit sets the resume_from_noirq flag in the bsw_pwm_dev_desc
struct, so that Cherry Trail PWM controllers will be resumed in the
no-irq phase. Together with the device-link added by the pwm-get this
ensures that the PWM controller will be on when the troublesome PS0
method runs, which stops it from poking the PWM controller.

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/acpi/acpi_lpss.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 5e2bfbcf526f..67892fc0b822 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -257,6 +257,7 @@ 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,
+	.resume_from_noirq = true,
 };
 
 static const struct lpss_device_desc byt_uart_dev_desc = {
-- 
2.26.2


  reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-17 13:37 [PATCH v5 00/16] acpi/pwm/i915: Convert pwm-crc and i915 driver's PWM code to use the atomic PWM API Hans de Goede
2020-07-17 13:37 ` Hans de Goede [this message]
2020-07-17 13:37 ` [PATCH v5 02/16] ACPI / LPSS: Save Cherry Trail PWM ctx registers only once (at activation) Hans de Goede
2020-07-17 13:37 ` [PATCH v5 03/16] pwm: lpss: Fix off by one error in base_unit math in pwm_lpss_prepare() Hans de Goede
2020-07-17 13:37 ` [PATCH v5 04/16] pwm: lpss: Add range limit check for the base_unit register value Hans de Goede
2020-07-17 13:37 ` [PATCH v5 05/16] pwm: lpss: Add pwm_lpss_prepare_enable() helper Hans de Goede
2020-07-28 18:45   ` Andy Shevchenko
2020-07-28 19:49     ` Hans de Goede
2020-07-17 13:37 ` [PATCH v5 06/16] pwm: lpss: Use pwm_lpss_apply() when restoring state on resume Hans de Goede
2020-07-28 18:57   ` Andy Shevchenko
2020-07-28 19:55     ` Hans de Goede
2020-07-29  8:12       ` Andy Shevchenko
2020-08-02 20:51         ` Hans de Goede
2020-08-03  8:41           ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 07/16] pwm: crc: Fix period / duty_cycle times being off by a factor of 256 Hans de Goede
2020-07-28 19:36   ` Andy Shevchenko
2020-07-28 20:00     ` Hans de Goede
2020-07-29  8:13   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 08/16] pwm: crc: Fix off-by-one error in the clock-divider calculations Hans de Goede
2020-07-29 10:28   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 09/16] pwm: crc: Fix period changes not having any effect Hans de Goede
2020-07-29 10:30   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 10/16] pwm: crc: Enable/disable PWM output on enable/disable Hans de Goede
2020-07-29 10:32   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 11/16] pwm: crc: Implement apply() method to support the new atomic PWM API Hans de Goede
2020-07-29 10:51   ` Andy Shevchenko
2020-07-17 13:37 ` [PATCH v5 12/16] pwm: crc: Implement get_state() method Hans de Goede
2020-07-17 13:37 ` [PATCH v5 13/16] drm/i915: panel: Add get_vbt_pwm_freq() helper Hans de Goede
2020-07-17 13:37 ` [PATCH v5 14/16] drm/i915: panel: Honor the VBT PWM frequency for devs with an external PWM controller Hans de Goede
2020-07-17 13:44 ` [PATCH v5 15/16] drm/i915: panel: Honor the VBT PWM min setting " Hans de Goede
2020-07-17 13:44   ` [PATCH v5 16/16] drm/i915: panel: Use atomic PWM API " Hans de Goede
2020-07-27  7:41 ` [PATCH v5 00/16] acpi/pwm/i915: Convert pwm-crc and i915 driver's PWM code to use the atomic PWM API Thierry Reding
2020-07-29  8:23   ` Andy Shevchenko
2020-07-29  9:32     ` Hans de Goede
2020-07-30  9:26       ` Thierry Reding
2020-08-01 14:33         ` Hans de Goede
2020-07-29 10:54 ` Andy Shevchenko
2020-08-01 14:38   ` Hans de Goede
2020-08-02 11:25     ` Andy Shevchenko
2020-08-02 19:43       ` Hans de Goede

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