On Thu, Feb 11, 2021 at 05:22:05AM +0000, Lee, Shawn C wrote: > > On Wed, Feb 10, 2021 at 04:51 p.m, Ville Syrjälä wrote: > >On Mon, Feb 08, 2021 at 01:31:57PM +0000, Lee, Shawn C wrote: > >> On Fri, Feb 05, 2021, at 8:26 p.m, Ville Syrjälä wrote: > >> >On Mon, Feb 01, 2021 at 11:02:28PM +0800, Lee Shawn C wrote: > >> >> According to Bspec #20124, max link rate table for DP was updated > >> >> at BDB version 230. Max link rate can support upto UHBR. > >> >> > >> >> After migrate to BDB v230, the definition for LBR, HBR2 and HBR3 > >> >> were changed. For backward compatibility. If BDB version was from > >> >> 216 to 229. Driver have to follow original rule to configure DP max > >> >> link rate value from VBT. > >> >> > >> >> Cc: Ville Syrjala <[email protected]> > >> >> Cc: Imre Deak <[email protected]> > >> >> Cc: Jani Nikula <[email protected]> > >> >> Cc: Cooper Chiou <[email protected]> > >> >> Cc: William Tseng <[email protected]> > >> >> Signed-off-by: Lee Shawn C <[email protected]> > >> >> --- > >> >> drivers/gpu/drm/i915/display/intel_bios.c | 24 ++++++++++++++++++- > >> >> drivers/gpu/drm/i915/display/intel_vbt_defs.h | 14 +++++++---- > >> >> 2 files changed, 32 insertions(+), 6 deletions(-) > >> >> > >> >> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c > >> >> b/drivers/gpu/drm/i915/display/intel_bios.c > >> >> index 04337ac6f8c4..be1f732e6550 100644 > >> >> --- a/drivers/gpu/drm/i915/display/intel_bios.c > >> >> +++ b/drivers/gpu/drm/i915/display/intel_bios.c > >> >> @@ -1876,7 +1876,15 @@ static void parse_ddi_port(struct > >> >> drm_i915_private *dev_priv, > >> >> /* DP max link rate for CNL+ */ > >> >> if (bdb_version >= 216) { > >> >> switch (child->dp_max_link_rate) { > >> >> - default: > >> >> + case VBT_DP_MAX_LINK_RATE_UHBR20: > >> >> + info->dp_max_link_rate = 2000000; > >> >> + break; > >> >> + case VBT_DP_MAX_LINK_RATE_UHBR13P5: > >> >> + info->dp_max_link_rate = 1350000; > >> >> + break; > >> >> + case VBT_DP_MAX_LINK_RATE_UHBR10: > >> >> + info->dp_max_link_rate = 1000000; > >> >> + break; > >> >> case VBT_DP_MAX_LINK_RATE_HBR3: > >> >> info->dp_max_link_rate = 810000; > >> >> break; > >> >> @@ -1889,7 +1897,21 @@ static void parse_ddi_port(struct > >> >> drm_i915_private *dev_priv, > >> >> case VBT_DP_MAX_LINK_RATE_LBR: > >> >> info->dp_max_link_rate = 162000; > >> >> break; > >> >> + case VBT_DP_MAX_LINK_RATE_DEFAULT: > >> >> + default: > >> >> + info->dp_max_link_rate = 0; > >> >> + break; > >> >> + } > >> >> + > >> >> + if (bdb_version < 230) { > >> >> + if (child->dp_max_link_rate == > >> >> VBT_DP_MAX_LINK_RATE_DEFAULT) > >> >> + info->dp_max_link_rate = 810000; > >> >> + else if (child->dp_max_link_rate == > >> >> VBT_DP_MAX_LINK_RATE_LBR) > >> >> + info->dp_max_link_rate = 540000; > >> >> + else if (child->dp_max_link_rate == > >> >> VBT_DP_MAX_LINK_RATE_HBR2) > >> >> + info->dp_max_link_rate = 162000; > >> >> } > >> > > >> >I would split this into two separate functions, one does the new mapping, > >> >the other the old mapping. > >> > > >> > >> I will split this into two separate functions in patch v2. > > > >Actually looking through the VBT history this seems to have been > >retroactively changed for already rev 216+ to follow the new > >definitions. And naturally no actual explanation given. So it's > >the same old VBT==snafu as always. > > > >I guess the real question is whether any machines migth have shipped > >that depened on the old defitions? Unless someone manages to > >find that out I think we might just have to change this to follow > >only the new style and hope we don't regress a lot of machines. > > > > Agree that we should just have the change follow new definition. > But as you mentioned, we are not sure any machines have shipped > with the old definition. :( > > In my opinion, we should follow the new style. If we got bug report, > then we can consider to add some codes for backward compatible.
I went trawling in some really dark waters and found out that Windows seems to do what you did originally, ie. use the old definition for 216+, and the new definition for 230+. So we should just do the same. -- Ville Syrjälä Intel _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
