[AMD Official Use Only - AMD Internal Distribution Only] Thanks a lot @Alex Deucher!
It would be helpful to get feedback from display folks @Pillai, Aurabindo and @Li, Roman as well. Best regards, Srini > -----Original Message----- > From: Alex Deucher <[email protected]> > Sent: Tuesday, March 24, 2026 7:43 PM > To: SHANMUGAM, SRINIVASAN <[email protected]> > Cc: Deucher, Alexander <[email protected]>; amd- > [email protected]; Li, Roman <[email protected]> > Subject: Re: [PATCH 2/3] drm/amd/display: Fix DCE LVDS handling > > On Tue, Mar 24, 2026 at 10:10 AM SHANMUGAM, SRINIVASAN > <[email protected]> wrote: > > > > [AMD Official Use Only - AMD Internal Distribution Only] > > > > Hi Alex, > > > > Do we need to handle similar cases in DCN resource paths (e.g., > > dcn10/dcn401) > ie., dcn401_resource.c and dcn10_resource.c? > > They also reject encoder creation when hpd_source is out of range, but > > unlike DCE they don’t have no_hpd handling. Or is this not applicable > > since DCN doesn’t support LVDS/no-HPD cases? > > Correct. Everything should have HPD for DCN. > > Alex > > > > > Thanks, > > Srini > > > > > -----Original Message----- > > > From: Alex Deucher <[email protected]> > > > Sent: Tuesday, March 24, 2026 6:18 PM > > > To: Deucher, Alexander <[email protected]> > > > Cc: [email protected]; SHANMUGAM, SRINIVASAN > > > <[email protected]>; Li, Roman > <[email protected]> > > > Subject: Re: [PATCH 2/3] drm/amd/display: Fix DCE LVDS handling > > > > > > Ping? This fixes a regression on LVDS systems. > > > > > > Alex > > > > > > On Mon, Mar 23, 2026 at 11:41 AM Alex Deucher > > > <[email protected]> > > > wrote: > > > > > > > > LVDS does not use an HPD pin so it may be invalid. Handle this > > > > case correctly in link encoder creation. > > > > > > > > Fixes: 7c8fb3b8e9ba ("drm/amd/display: Add hpd_source index check > > > > for > > > > DCE60/80/100/110/112/120 link encoders") > > > > Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/5012 > > > > Cc: Srinivasan Shanmugam <[email protected]> > > > > Cc: Roman Li <[email protected]> > > > > Signed-off-by: Alex Deucher <[email protected]> > > > > --- > > > > .../display/dc/resource/dce100/dce100_resource.c | 6 ++---- > > > > .../display/dc/resource/dce110/dce110_resource.c | 5 +++-- > > > > .../display/dc/resource/dce112/dce112_resource.c | 5 +++-- > > > > .../display/dc/resource/dce120/dce120_resource.c | 5 +++-- > > > > .../amd/display/dc/resource/dce60/dce60_resource.c | 14 > > > > ++++++-------- .../amd/display/dc/resource/dce80/dce80_resource.c > > > > ++++++| > > > > 6 ++---- > > > > 6 files changed, 19 insertions(+), 22 deletions(-) > > > > > > > > diff --git > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce100/dce100_resource.c > > > > b/drivers/gpu/drm/amd/display/dc/resource/dce100/dce100_resource.c > > > > index 05f7ff60f8f5a..2b884e28727ba 100644 > > > > --- > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce100/dce100_resource.c > > > > +++ b/drivers/gpu/drm/amd/display/dc/resource/dce100/dce100_resour > > > > +++ ce.c > > > > @@ -651,9 +651,6 @@ static struct link_encoder > *dce100_link_encoder_create( > > > > return &enc110->base; > > > > } > > > > > > > > - if (enc_init_data->hpd_source >= ARRAY_SIZE(link_enc_hpd_regs)) > > > > - return NULL; > > > > - > > > > link_regs_id = > > > > > > > > map_transmitter_id_to_phy_instance(enc_init_data->transmitter); > > > > > > > > @@ -662,7 +659,8 @@ static struct link_encoder > *dce100_link_encoder_create( > > > > &link_enc_feature, > > > > &link_enc_regs[link_regs_id], > > > > > > > > &link_enc_aux_regs[enc_init_data->channel - 1], > > > > - > > > > &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > + enc_init_data->hpd_source >= > > > ARRAY_SIZE(link_enc_hpd_regs) ? > > > > + NULL : > > > > + &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > return &enc110->base; > > > > } > > > > > > > > diff --git > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce110/dce110_resource.c > > > > b/drivers/gpu/drm/amd/display/dc/resource/dce110/dce110_resource.c > > > > index 7c09825cd9bd3..d957598911cbc 100644 > > > > --- > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce110/dce110_resource.c > > > > +++ b/drivers/gpu/drm/amd/display/dc/resource/dce110/dce110_resour > > > > +++ ce.c > > > > @@ -672,7 +672,7 @@ static struct link_encoder > *dce110_link_encoder_create( > > > > kzalloc(sizeof(struct dce110_link_encoder), GFP_KERNEL); > > > > int link_regs_id; > > > > > > > > - if (!enc110 || enc_init_data->hpd_source >= > > > ARRAY_SIZE(link_enc_hpd_regs)) > > > > + if (!enc110) > > > > return NULL; > > > > > > > > link_regs_id = > > > > @@ -683,7 +683,8 @@ static struct link_encoder > *dce110_link_encoder_create( > > > > &link_enc_feature, > > > > &link_enc_regs[link_regs_id], > > > > > > > > &link_enc_aux_regs[enc_init_data->channel - 1], > > > > - > > > > &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > + enc_init_data->hpd_source >= > > > ARRAY_SIZE(link_enc_hpd_regs) ? > > > > + NULL : > > > > + &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > return &enc110->base; > > > > } > > > > > > > > diff --git > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce112/dce112_resource.c > > > > b/drivers/gpu/drm/amd/display/dc/resource/dce112/dce112_resource.c > > > > index 3f0a6bc4dcc23..1cce903d477aa 100644 > > > > --- > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce112/dce112_resource.c > > > > +++ b/drivers/gpu/drm/amd/display/dc/resource/dce112/dce112_resour > > > > +++ ce.c > > > > @@ -633,7 +633,7 @@ static struct link_encoder > *dce112_link_encoder_create( > > > > kzalloc(sizeof(struct dce110_link_encoder), GFP_KERNEL); > > > > int link_regs_id; > > > > > > > > - if (!enc110 || enc_init_data->hpd_source >= > > > ARRAY_SIZE(link_enc_hpd_regs)) > > > > + if (!enc110) > > > > return NULL; > > > > > > > > link_regs_id = > > > > @@ -644,7 +644,8 @@ static struct link_encoder > *dce112_link_encoder_create( > > > > &link_enc_feature, > > > > &link_enc_regs[link_regs_id], > > > > > > > > &link_enc_aux_regs[enc_init_data->channel - 1], > > > > - > > > > &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > + enc_init_data->hpd_source >= > > > ARRAY_SIZE(link_enc_hpd_regs) ? > > > > + NULL : > > > > + &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > return &enc110->base; > > > > } > > > > > > > > diff --git > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce120/dce120_resource.c > > > > b/drivers/gpu/drm/amd/display/dc/resource/dce120/dce120_resource.c > > > > index 92890784caa6e..8b568be20a77b 100644 > > > > --- > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce120/dce120_resource.c > > > > +++ b/drivers/gpu/drm/amd/display/dc/resource/dce120/dce120_resour > > > > +++ ce.c > > > > @@ -717,7 +717,7 @@ static struct link_encoder > *dce120_link_encoder_create( > > > > kzalloc(sizeof(struct dce110_link_encoder), GFP_KERNEL); > > > > int link_regs_id; > > > > > > > > - if (!enc110 || enc_init_data->hpd_source >= > > > ARRAY_SIZE(link_enc_hpd_regs)) > > > > + if (!enc110) > > > > return NULL; > > > > > > > > link_regs_id = > > > > @@ -728,7 +728,8 @@ static struct link_encoder > *dce120_link_encoder_create( > > > > &link_enc_feature, > > > > &link_enc_regs[link_regs_id], > > > > > > > > &link_enc_aux_regs[enc_init_data->channel - 1], > > > > - > > > > &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > + enc_init_data->hpd_source >= > > > ARRAY_SIZE(link_enc_hpd_regs) ? > > > > + NULL : > > > > + &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > > > > > return &enc110->base; > > > > } > > > > diff --git > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce60/dce60_resource.c > > > > b/drivers/gpu/drm/amd/display/dc/resource/dce60/dce60_resource.c > > > > index d41d24b76c11f..2f5ee9d8536af 100644 > > > > --- > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce60/dce60_resource.c > > > > +++ b/drivers/gpu/drm/amd/display/dc/resource/dce60/dce60_resource > > > > +++ .c > > > > @@ -747,18 +747,16 @@ static struct link_encoder > > > *dce60_link_encoder_create( > > > > return &enc110->base; > > > > } > > > > > > > > - if (enc_init_data->hpd_source >= ARRAY_SIZE(link_enc_hpd_regs)) > > > > - return NULL; > > > > - > > > > link_regs_id = > > > > > > > > map_transmitter_id_to_phy_instance(enc_init_data->transmitter); > > > > > > > > dce60_link_encoder_construct(enc110, > > > > - enc_init_data, > > > > - &link_enc_feature, > > > > - &link_enc_regs[link_regs_id], > > > > - > > > > &link_enc_aux_regs[enc_init_data->channel - 1], > > > > - > > > > &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > + enc_init_data, > > > > + &link_enc_feature, > > > > + &link_enc_regs[link_regs_id], > > > > + > > > > &link_enc_aux_regs[enc_init_data->channel - 1], > > > > + enc_init_data->hpd_source >= > > > ARRAY_SIZE(link_enc_hpd_regs) ? > > > > + NULL : > > > > + &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > return &enc110->base; > > > > } > > > > > > > > diff --git > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce80/dce80_resource.c > > > > b/drivers/gpu/drm/amd/display/dc/resource/dce80/dce80_resource.c > > > > index a68e799d58854..406705fac7d64 100644 > > > > --- > > > > a/drivers/gpu/drm/amd/display/dc/resource/dce80/dce80_resource.c > > > > +++ b/drivers/gpu/drm/amd/display/dc/resource/dce80/dce80_resource > > > > +++ .c > > > > @@ -753,9 +753,6 @@ static struct link_encoder > *dce80_link_encoder_create( > > > > return &enc110->base; > > > > } > > > > > > > > - if (enc_init_data->hpd_source >= ARRAY_SIZE(link_enc_hpd_regs)) > > > > - return NULL; > > > > - > > > > link_regs_id = > > > > > > > > map_transmitter_id_to_phy_instance(enc_init_data->transmitter); > > > > > > > > @@ -764,7 +761,8 @@ static struct link_encoder > *dce80_link_encoder_create( > > > > &link_enc_feature, > > > > &link_enc_regs[link_regs_id], > > > > > > > > &link_enc_aux_regs[enc_init_data->channel - 1], > > > > - > > > > &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > + enc_init_data->hpd_source >= > > > ARRAY_SIZE(link_enc_hpd_regs) ? > > > > + NULL : > > > > + &link_enc_hpd_regs[enc_init_data->hpd_source]); > > > > return &enc110->base; > > > > } > > > > > > > > -- > > > > 2.53.0 > > > >
