Re: [Intel-gfx] [PATCH v2] drm/i915/display: split DISPLAY_VER 9 and 10 in intel_setup_outputs()

[Lucas De Marchi <lucas.demarchi@intel.com>]

On Thu, Jul 22, 2021 at 10:57:09PM -0700, Matt Roper wrote:
>On Thu, Jul 22, 2021 at 04:29:22PM -0700, Lucas De Marchi wrote:
>> Commit 5a9d38b20a5a ("drm/i915/display: hide workaround for broken vbt
>> in intel_bios.c") moved the workaround for broken or missing VBT to
>> intel_bios.c. However is_port_valid() only protects the handling of
>> different skus of the same display version. Since in
>> intel_setup_outputs() we share the code path with version 9, this would
>> also create port F for SKL/KBL, which does not exist.
>>
>> Missing VBT can be reproduced when starting a headless QEMU with no
>> opregion available.
>>
>> Avoid the issue by splitting versions 9 and 10 in intel_setup_outputs(),
>> which also makes it more clear what code path it's taking for each
>> version.
>
>Or we could just drop the PORT_F line.  We've slowly been dropping bits
>and pieces of CNL support from the driver for a while now since all the
>hardware that came out had fused off graphics/display; that leaves GLK
>as the only real platform with display version 10, and it's already
>handled in its own condition branch above.

no, that was my suggestion when I did this for the first time. Review
from Ville last time was that we should either remove it completely or
not at all, instead of dropping some pieces. At the time I started a
series to remove it, but never completed.

https://patchwork.freedesktop.org/patch/428168/?series=88988&rev=1#comment_768918

I will try to come back to that series again, but it's not something to
go to -fixes, so I'd prefer to keep this patch.

thanks
Lucas De Marchi

>
>
>Matt
>
>>
>> v2: move generic display version after Geminilake since that one has
>> a different set of outputs
>>
>> Fixes: 5a9d38b20a5a ("drm/i915/display: hide workaround for broken vbt in intel_bios.c")
>> Cc: Jani Nikula <jani.nikula@intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Reported-by: Christoph Hellwig <hch@infradead.org>
>> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
>> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_display.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
>> index c274bfb8e549..3f5383f3c744 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display.c
>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>> @@ -11376,13 +11376,19 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv)
>>  		intel_ddi_init(dev_priv, PORT_B);
>>  		intel_ddi_init(dev_priv, PORT_C);
>>  		vlv_dsi_init(dev_priv);
>> -	} else if (DISPLAY_VER(dev_priv) >= 9) {
>> +	} else if (DISPLAY_VER(dev_priv) == 10) {
>>  		intel_ddi_init(dev_priv, PORT_A);
>>  		intel_ddi_init(dev_priv, PORT_B);
>>  		intel_ddi_init(dev_priv, PORT_C);
>>  		intel_ddi_init(dev_priv, PORT_D);
>>  		intel_ddi_init(dev_priv, PORT_E);
>>  		intel_ddi_init(dev_priv, PORT_F);
>> +	} else if (DISPLAY_VER(dev_priv) >= 9) {
>> +		intel_ddi_init(dev_priv, PORT_A);
>> +		intel_ddi_init(dev_priv, PORT_B);
>> +		intel_ddi_init(dev_priv, PORT_C);
>> +		intel_ddi_init(dev_priv, PORT_D);
>> +		intel_ddi_init(dev_priv, PORT_E);
>>  	} else if (HAS_DDI(dev_priv)) {
>>  		u32 found;
>>
>> --
>> 2.31.1
>>
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>> Intel-gfx@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
>-- 
>Matt Roper
>Graphics Software Engineer
>VTT-OSGC Platform Enablement
>Intel Corporation
>(916) 356-2795
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