[Intel-gfx] [PATCH 04/12] drm/i915/bios: limit default outputs to ports A through F

[Lucas De Marchi]

On Tue, Feb 23, 2021 at 03:34:51PM +0200, Jani Nikula wrote:
>On Wed, 17 Feb 2021, Lucas De Marchi <lucas.demarchi at intel.com> wrote:
>> On Wed, Feb 17, 2021 at 09:49:57PM +0200, Jani Nikula wrote:
>>>On Wed, 17 Feb 2021, Lucas De Marchi <lucas.demarchi at intel.com> wrote:
>>>> On Wed, Feb 17, 2021 at 09:23:00AM -0800, Lucas De Marchi wrote:
>>>>>On Wed, Feb 17, 2021 at 07:03:34PM +0200, Jani Nikula wrote:
>>>>>>With the defaults limited to non-TypeC ports in commit 828ccb31cf41
>>>>>>("drm/i915/icl: Add TypeC ports only if VBT is present"), this should be
>>>>>>a no-op, but clarifies the code and prepares for subsequent changes.
>>>>>>
>>>>>>Cc: Lucas De Marchi <lucas.demarchi 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/display/intel_bios.c | 3 ++-
>>>>>>1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>>
>>>>>>diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
>>>>>>index e9cb15aa2f5a..b9d99324d66d 100644
>>>>>>--- a/drivers/gpu/drm/i915/display/intel_bios.c
>>>>>>+++ b/drivers/gpu/drm/i915/display/intel_bios.c
>>>>>>@@ -2057,11 +2057,12 @@ static void
>>>>>>init_vbt_missing_defaults(struct drm_i915_private *i915)
>>>>>>{
>>>>>>	enum port port;
>>>>>>+	int ports = PORT_A | PORT_B | PORT_C | PORT_D | PORT_E | PORT_F;
>>>>>
>>>>>
>>>>>I'd not spread the knowledge of what port uses tc phy like this.
>>>>>It's painful to maintain.
>>>
>>>Umm, this wasn't meant to have anything to do with tc, really. Granted,
>>>the commit message is misleading.
>>
>> ok, makes more sense now. I don't want us to keep updating this function
>> when the ports change on new platforms.
>
>Agreed.
>
>>
>>>
>>>>
>>>> also, not sure how this clarifies things if PORT_TC1 aliases PORT_D,
>>>> so I'd just drop this patch
>>>
>>>The point is that I'd like to reduce the number of ports set up by
>>>default, perhaps even further than this. It's a bit silly to generate 9
>>>dummy child devices on certain platforms when there's no VBT.
>>
>> ok. So what would be the devices without vbt? I remember relying on this
>> for e.g. dg1 before we could read it.
>
>If it were just for enabling, I'd start some igt tool to generate a
>basic VBT to use with i915.vbt_firmware and the firmware loader. It's
>the existing products that ended up depending on the defaults that are
>the real issue I think.
>
>> What other platforms should we care about? And for those, should we
>> really care about ports E and F or could we reduce it to, say the first
>> 4?
>
>IIRC they were some Haswell or Broadwell era Chromebooks. They probably
>don't use very many ports, but in theory it could be A-D,F on DDI
>platforms (E requires VBT child device). On gen 11 it could be A-E, with
>F requiring VBT child device.
>
>A-F covers all cases, but does not try to create G-I or any further
>future ports.


ok, thanks for confirming.


Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>

Lucas De Marchi


>
>
>BR,
>Jani.
>
>
>>
>> thanks
>> Lucas De Marchi
>>
>>>
>>>
>>>BR,
>>>Jani.
>>>
>>>>
>>>> Lucas De Marchi
>>>>
>>>>>Lucas De Marchi
>>>>>
>>>>>>
>>>>>>	if (!HAS_DDI(i915) && !IS_CHERRYVIEW(i915))
>>>>>>		return;
>>>>>>
>>>>>>-	for_each_port(port) {
>>>>>>+	for_each_port_masked(port, ports) {
>>>>>>		struct ddi_vbt_port_info *info =
>>>>>>			&i915->vbt.ddi_port_info[port];
>>>>>>		enum phy phy = intel_port_to_phy(i915, port);
>>>>>>--
>>>>>>2.20.1
>>>>>>
>>>> _______________________________________________
>>>> Intel-gfx mailing list
>>>> Intel-gfx at lists.freedesktop.org
>>>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>>>
>>>--
>>>Jani Nikula, Intel Open Source Graphics Center
>
>-- 
>Jani Nikula, Intel Open Source Graphics Center