[Intel-gfx] [PATCH 2/2] drm/i915/vbt: split out defaults that are set when there is no VBT

[Jani Nikula]

On Mon, 13 Mar 2017, Manasi Navare <manasi.d.navare at intel.com> wrote:
> On Mon, Mar 13, 2017 at 11:55:31AM +0200, Jani Nikula wrote:
>> On Sat, 11 Mar 2017, Manasi Navare <manasi.d.navare at intel.com> wrote:
>> > On Fri, Mar 10, 2017 at 03:27:58PM +0200, Jani Nikula wrote:
>> >> The main thing are the DDI ports. If there's a VBT that says there are
>> >> no outputs, we should trust that, and not have semi-random
>> >> defaults. Unfortunately, the defaults have resulted in some Chromebooks
>> >> without VBT to rely on this behaviour, so we split out the defaults for
>> >> the missing VBT case.
>> >> 
>> >> Cc: Manasi Navare <manasi.d.navare at intel.com>
>> >> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> >> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
>> >> ---
>> >>  drivers/gpu/drm/i915/intel_bios.c | 17 ++++++++++++++++-
>> >>  1 file changed, 16 insertions(+), 1 deletion(-)
>> >> 
>> >> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
>> >> index 710988d72253..639d45c1dd2e 100644
>> >> --- a/drivers/gpu/drm/i915/intel_bios.c
>> >> +++ b/drivers/gpu/drm/i915/intel_bios.c
>> >> @@ -1341,6 +1341,7 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
>> >>  	return;
>> >>  }
>> >>  
>> >> +/* Common defaults which may be overridden by VBT. */
>> >>  static void
>> >>  init_vbt_defaults(struct drm_i915_private *dev_priv)
>> >>  {
>> >> @@ -1377,6 +1378,18 @@ init_vbt_defaults(struct drm_i915_private *dev_priv)
>> >>  			&dev_priv->vbt.ddi_port_info[port];
>> >>  
>> >>  		info->hdmi_level_shift = HDMI_LEVEL_SHIFT_UNKNOWN;
>> >> +	}
>> >> +}
>> >> +
>> >> +/* Defaults to initialize only if there is no VBT. */
>> >> +static void
>> >> +init_vbt_missing_defaults(struct drm_i915_private *dev_priv)
>> >> +{
>> >> +	enum port port;
>> >> +
>> >> +	for (port = PORT_A; port < I915_MAX_PORTS; port++) {
>> >> +		struct ddi_vbt_port_info *info =
>> >> +			&dev_priv->vbt.ddi_port_info[port];
>> >>  
>> >>  		info->supports_dvi = (port != PORT_A && port != PORT_E);
>> >>  		info->supports_hdmi = info->supports_dvi;
>> >> @@ -1516,8 +1529,10 @@ void intel_bios_init(struct drm_i915_private *dev_priv)
>> >>  	parse_ddi_ports(dev_priv, bdb);
>> >>  
>> >>  out:
>> >> -	if (!vbt)
>> >> +	if (!vbt) {
>> >>  		DRM_INFO("Failed to find VBIOS tables (VBT)\n");
>> >> +		init_vbt_missing_defaults(dev_priv);
>> >> +	}
>> >
>> > So in case there is no VBT, this will set supports_DP flag on Port A.
>> > What is there is no VBT and there is no eDP on Port A?
>> > In this case it will still try to link train on Port A and fail..?
>> > I am not sure if this case exists, but just a thought looking at it.
>> 
>> It's possible the case exists, but the point is that the behaviour for
>> the no-VBT case remains the same before and after this patch.
>> 
>> BR,
>> Jani.
>> 
>>
>
> Ok agreed. In that case Reviewed-by: Manasi Navare
> <manasi.d.navare at intel.com>

Pushed to drm-intel-next-queued, thanks for the review.

I really hope there are no machines out there that have a crippled VBT
with no child device config. I guess we'll find out...

BR,
Jani.


>
> Regards
> Manasi
>
>  
>> > If such a case does not exist, then this will solve our problem of
>> > current failures because leaving defaults on Port A. So in that case
>> > it lgtm.
>> >
>> > Regards
>> > Manasi
>> >
>> >
>> >>  
>> >>  	if (bios)
>> >>  		pci_unmap_rom(pdev, bios);
>> >> -- 
>> >> 2.1.4
>> >> 
>> 
>> -- 
>> Jani Nikula, Intel Open Source Technology Center

-- 
Jani Nikula, Intel Open Source Technology Center