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From:   Aditya Garg <gargaditya08@live.com>
To:     Alex Deucher <alexdeucher@gmail.com>
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Subject: Re: [PATCH RESEND] drm/amd/display: Force link_rate as LINK_RATE_RBR2
 for 2018 15" Apple Retina panels
Thread-Topic: [PATCH RESEND] drm/amd/display: Force link_rate as
 LINK_RATE_RBR2 for 2018 15" Apple Retina panels
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Date:   Fri, 28 Jan 2022 13:06:52 +0000
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Hi Alex

> On 27-Jan-2022, at 11:06 PM, Alex Deucher <alexdeucher@gmail.com> wrote:
>=20
> C style comments please.
Shall be fixed in v2
>  I'll let one of the display guys comment on
> the rest of the patch.  Seems reasonable, we have a similar quirk for
> the Apple MBP 2017 15" Retina panel later in this function.  Could you
> move this next to the other quirk?
I guess moving it next to the other quirk may break the functionality of th=
is quirk, cause the MBP 2018 one involves stuff regarding firmware revision=
 as well. The original patch applies the quirk after the following lines of=
 the code :-

=09
	core_link_read_dpcd(
		link,
		DP_SINK_HW_REVISION_START,
		(uint8_t *)&dp_hw_fw_revision,
		sizeof(dp_hw_fw_revision));

	link->dpcd_caps.sink_hw_revision =3D
		dp_hw_fw_revision.ieee_hw_rev;

	memmove(
		link->dpcd_caps.sink_fw_revision,
		dp_hw_fw_revision.ieee_fw_rev,
		sizeof(dp_hw_fw_revision.ieee_fw_rev));

Which seem to related to the firmware stuff. Moving it along with the 2017 =
quirk doesn't sound right to me, as this shall move the quirk BEFORE these =
lines of code instead. Maybe the author also knowingly added the quirk afte=
r these lines of code?

As a workaround, could we move the 2017 quirk later, instead of moving the =
2018 quirk before? This sounds more logical to me.

Regards
Aditya