On Mon, 13 Mar 2017, Manasi Navare <manasi.d.navare@xxxxxxxxx> wrote:
> On Mon, Mar 13, 2017 at 11:55:31AM +0200, Jani Nikula wrote:
>> On Sat, 11 Mar 2017, Manasi Navare <manasi.d.navare@xxxxxxxxx> 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@xxxxxxxxx>
>> >> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>> >> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
>> >> ---
>> >> 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@xxxxxxxxx>
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
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