Quoting Lucas De Marchi (2025-02-07 19:41:11-03:00)
>On Fri, Feb 07, 2025 at 11:54:03PM +0200, Ville Syrjälä wrote:
>>From: Ville Syrjälä <ville.syrj...@linux.intel.com>
>>
>>Something has changed in the hardware on LNL/BMG because
>>HDMI outputs no longer have the extra scanline offset.
>>
>>I confirmed that MTL still has the old behaviour, which
>>is a bit weird since both MTL and BMG have display ver 14
>>vs. LNL is version 20. But can't argue with actual
>>hardware behaviour.
>
><6>[ 210.368608] xe 0000:03:00.0: [drm] Found battlemage (device ID e20b)
>discrete display version 14.01 stepping B0
>vs
><6>[ 412.999204] i915 0000:00:02.0: [drm] Found meteorlake (device ID 7d55)
>integrated display version 14.00 stepping C0
>
>So 14.01 vs 14.00. In the driver:
>
>static const struct {
>
> u16 ver;
> u16 rel;
> const struct intel_display_device_info *display;
>} gmdid_display_map[] = {
> { 14, 0, &xe_lpdp_display },
> { 14, 1, &xe2_hpd_display },
> ...
>}
>
>So maybe we need to check for the full version >= 1401 instead?
Yeah, I think just checking for version >= 14.01 would make sense here.
>
>+Matt Roper, +Gustavo who may know the right bspec to confirm this
>change in behavior
I haven't found any bspec that explains the behavior of the counter
outside of the bspec page for the scanline register itself, which seems
to have the same description across different platforms.
--
Gustavo Sousa
>
>Lucas De Marchi
>
>>
>>Ville Syrjälä (3):
>> drm/i915: Fix scanline_offset for LNL+ and BMG+
>> drm/i915: Reverse the scanline_offset if ladder
>> drm/i915: Replace the HAS_DDI() in intel_crtc_scanline_offset() with
>> specific platform checks
>>
>> drivers/gpu/drm/i915/display/intel_vblank.c | 13 ++++++++-----
>> 1 file changed, 8 insertions(+), 5 deletions(-)
>>
>>--
>>2.45.3
>>
