[Intel-gfx] [PATCH] drm/i915/fbc: disable FBC on Nightfury board

[Lee, Shawn C]

On Fri, Sept. 11, 2020, 2:21 p.m. Ville Syrjälä wrote:
>On Thu, Aug 27, 2020 at 01:51:29PM +0800, Lee Shawn C wrote:
>> Customer report random display flicker issue on Nightfury board.
>> And we found this problem might be caused by VT-d and FBC are both 
>> enabled. According to sighting report, it recommend to turn
>> drm/i915/fbc: disable FBC on Nightfury board
>> 
>> Customer report random display flicker issue on Nightfury board.
>> And we found this problem might be caused by VT-d and FBC are both 
>> enabled. According to sighting report, it recommend to turn FBC off to 
>> workaround this kind of issue.
>> 
>> This change refer to DMI BOARD_VENDOR and BOARD_NAME information to 
>> disable FBC.
>
>What is this "nightfury board" exactly?

It is chrome os project on CML platform. The board name is "nightfury".

>
>I think we're missing at least one fbc vs. vt-d w/a on some kbl/cfl/etc. era platforms:
>git://github.com/vsyrjala/linux.git  vtd_wa_1142
>
>> 
>> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
>> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
>> Cc: Jani Nikula <jani.nikula at intel.com>
>> Cc: William Tseng <william.tseng at intel.com>
>> Cc: Cooper Chiou <cooper.chiou at intel.com>
>> Signed-off-by: Lee Shawn C <shawn.c.lee at intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_fbc.c | 22 ++++++++++++++++++++++
>>  1 file changed, 22 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c 
>> b/drivers/gpu/drm/i915/display/intel_fbc.c
>> index 327af428d73f..20660fdbab36 100644
>> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
>> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
>> @@ -39,6 +39,7 @@
>>   */
>>  
>>  #include <drm/drm_fourcc.h>
>> +#include <linux/dmi.h>
>>  
>>  #include "i915_drv.h"
>>  #include "i915_trace.h"
>> @@ -1439,6 +1440,24 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
>>  	return 0;
>>  }
>>  
>> +static int intel_fbc_vtd_callback(const struct dmi_system_id *id) {
>> +	DRM_DEBUG_KMS("Disabling FBC to prevent screen flicker on %s device\n", id->ident);
>> +	return 1;
>> +}
>> +
>> +static const struct dmi_system_id intel_fbc_vtd_detect[] = {
>> +	{
>> +		.callback = intel_fbc_vtd_callback,
>> +		.ident = "Google Nightfury",
>> +		.matches = {
>> +			DMI_MATCH(DMI_BOARD_VENDOR, "Google"),
>> +			DMI_MATCH(DMI_BOARD_NAME, "Nightfury"),
>> +		},
>> +	},
>> +	{ }
>> +};
>> +
>>  static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv)  {
>>  	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */ @@ -1450,6 +1469,9 
>> @@ static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv)
>>  		return true;
>>  	}
>>  
>> +	if (dmi_check_system(intel_fbc_vtd_detect))
>> +		return true;
>> +
>>  	return false;
>>  }
>>  
>> --
>> 2.17.1
>
>--
>Ville Syrjälä
>Intel

Best regards,
Shawn