Re: [PATCH for stable 3.14 only 1/1] drm/i915: restore QUIRK_NO_PCH_PWM_ENABLE

[Jani Nikula <jani.nikula@intel.com>]

Greg, ping? Can we go with this?

On Mon, 28 Apr 2014, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Mon, Apr 28, 2014 at 01:10:07PM +0300, Jani Nikula wrote:
>> This reverts the bisected regressing
>> 
>> commit bc0bb9fd1c7810407ab810d204bbaecb255fddde
>> Author: Jani Nikula <jani.nikula@intel.com>
>> Date:   Thu Nov 14 12:14:29 2013 +0200
>> 
>>     drm/i915: remove QUIRK_NO_PCH_PWM_ENABLE
>> 
>> restoring QUIRK_NO_PCH_PWM_ENABLE for a couple of Dell XPS models which
>> broke in 3.14.
>> 
>> There is no such revert upstream. We have root caused and fixed the
>> issue upstream, without the quirk, with:
>> 
>> commit 39fbc9c8f6765959b55e0b127dd5c57df5a47d67
>> Author: Jani Nikula <jani.nikula@intel.com>
>> Date:   Wed Apr 9 11:22:06 2014 +0300
>> 
>>     drm/i915: check VBT for supported backlight type
>> 
>> and
>> 
>> commit c675949ec58ca50d5a3ae3c757892f1560f6e896
>> Author: Jani Nikula <jani.nikula@intel.com>
>> Date:   Wed Apr 9 11:31:37 2014 +0300
>> 
>>     drm/i915: do not setup backlight if not available according to VBT
>> 
>> While the commits are within the stable rules otherwise, and fix more
>> machines than just the regressed Dell XPS models, we feel backporting
>> them to stable may be too risky. The revert is limited to the broken
>> machines, and the impact should be effectively the same as what the
>> upstream commits do more generally.
>> 
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76276
>> Reported-by: Romain Francoise <romain@orebokech.com>
>> CC: Kamal Mostafa <kamal@canonical.com>
>> CC: Daniel Vetter <daniel@ffwll.ch>
>> CC: stable@vger.kernel.org (3.14 only)
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>
> Ack from my side since the VBT-based fix we have in 3.15 really is a bit
> too risky for backporting and should get the full -rc cycle for testing.
> But we just can't let existing users on affected hw hang in there for 2
> months.
> -Daniel
>
>> ---
>>  drivers/gpu/drm/i915/i915_drv.h      |  1 +
>>  drivers/gpu/drm/i915/intel_display.c | 16 ++++++++++++++++
>>  drivers/gpu/drm/i915/intel_panel.c   |  4 ++++
>>  3 files changed, 21 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index df77e20e3c3d..697f2150a997 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -734,6 +734,7 @@ enum intel_sbi_destination {
>>  #define QUIRK_PIPEA_FORCE (1<<0)
>>  #define QUIRK_LVDS_SSC_DISABLE (1<<1)
>>  #define QUIRK_INVERT_BRIGHTNESS (1<<2)
>> +#define QUIRK_NO_PCH_PWM_ENABLE (1<<3)
>>  
>>  struct intel_fbdev;
>>  struct intel_fbc_work;
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index 9b8a7c7ea7fc..963639d9049b 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -10771,6 +10771,17 @@ static void quirk_invert_brightness(struct drm_device *dev)
>>  	DRM_INFO("applying inverted panel brightness quirk\n");
>>  }
>>  
>> +/*
>> + * Some machines (Dell XPS13) suffer broken backlight controls if
>> + * BLM_PCH_PWM_ENABLE is set.
>> + */
>> +static void quirk_no_pcm_pwm_enable(struct drm_device *dev)
>> +{
>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>> +	dev_priv->quirks |= QUIRK_NO_PCH_PWM_ENABLE;
>> +	DRM_INFO("applying no-PCH_PWM_ENABLE quirk\n");
>> +}
>> +
>>  struct intel_quirk {
>>  	int device;
>>  	int subsystem_vendor;
>> @@ -10839,6 +10850,11 @@ static struct intel_quirk intel_quirks[] = {
>>  
>>  	/* Acer Aspire 4736Z */
>>  	{ 0x2a42, 0x1025, 0x0260, quirk_invert_brightness },
>> +
>> +	/* Dell XPS13 HD Sandy Bridge */
>> +	{ 0x0116, 0x1028, 0x052e, quirk_no_pcm_pwm_enable },
>> +	/* Dell XPS13 HD and XPS13 FHD Ivy Bridge */
>> +	{ 0x0166, 0x1028, 0x058b, quirk_no_pcm_pwm_enable },
>>  };
>>  
>>  static void intel_init_quirks(struct drm_device *dev)
>> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
>> index 079ea38f14d9..9f1d7a9300e8 100644
>> --- a/drivers/gpu/drm/i915/intel_panel.c
>> +++ b/drivers/gpu/drm/i915/intel_panel.c
>> @@ -671,6 +671,10 @@ static void pch_enable_backlight(struct intel_connector *connector)
>>  	pch_ctl2 = panel->backlight.max << 16;
>>  	I915_WRITE(BLC_PWM_PCH_CTL2, pch_ctl2);
>>  
>> +	/* XXX: transitional */
>> +	if (dev_priv->quirks & QUIRK_NO_PCH_PWM_ENABLE)
>> +		return;
>> +
>>  	pch_ctl1 = 0;
>>  	if (panel->backlight.active_low_pwm)
>>  		pch_ctl1 |= BLM_PCH_POLARITY;
>> -- 
>> 1.9.1
>> 
>
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
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-- 
Jani Nikula, Intel Open Source Technology Center