On Sat, 26 Nov 2022, Mikko Kovanen <mikko.kovanen@xxxxxxxxxxxxxx> wrote:
> intel_dsi->ports contains bitmask of enabled ports and correspondingly
> logic for selecting port for VBT packet sending must use port specific
> bitmask when deciding appropriate port.
>
> Fixes: 08c59dde71b7 ("drm/i915/dsi: fix VBT send packet port selection for ICL+")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Mikko Kovanen <mikko.kovanen@xxxxxxxxxxxxxx>
Holy crap, that's embarrassing! Thanks!
Despite the mistake, it always works for single-link DSI as well as port
A on dual-link DSI, which probably covers most use cases. It's the
commands targeted at port B (VLV+ DSI) or port C (ICL+ DSI) that go
haywire.
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dsi_vbt.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
> index 75e8cc4337c9..fce69fa446d5 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsi_vbt.c
> @@ -137,9 +137,9 @@ static enum port intel_dsi_seq_port_to_port(struct intel_dsi *intel_dsi,
> return ffs(intel_dsi->ports) - 1;
>
> if (seq_port) {
> - if (intel_dsi->ports & PORT_B)
> + if (intel_dsi->ports & BIT(PORT_B))
> return PORT_B;
> - else if (intel_dsi->ports & PORT_C)
> + else if (intel_dsi->ports & BIT(PORT_C))
> return PORT_C;
> }
--
Jani Nikula, Intel Open Source Graphics Center
