On Mon, 26 Jan 2026, Jonathan Cavitt <[email protected]> wrote:
> Static analysis issue:
>
> Bit operations are being performed using bit offsets computed from
> cpu_transcoder values, which may (albeit unlikely) be -1. Assert this
> is not the case when relevant.
>
> Signed-off-by: Jonathan Cavitt <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_ddi.c | 8 +++++++-
> drivers/gpu/drm/i915/display/intel_display.c | 5 +++++
> drivers/gpu/drm/i915/display/intel_dp.c | 3 +++
> drivers/gpu/drm/i915/display/intel_dp_mst.c | 3 +++
> 4 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> b/drivers/gpu/drm/i915/display/intel_ddi.c
> index d8739e2bb004..ec947c415e5f 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3876,7 +3876,8 @@ static void intel_ddi_set_idle_link_train(struct
> intel_dp *intel_dp,
> static bool intel_ddi_is_audio_enabled(struct intel_display *display,
> enum transcoder cpu_transcoder)
> {
> - if (cpu_transcoder == TRANSCODER_EDP)
> + if (cpu_transcoder == TRANSCODER_EDP ||
> + drm_WARN_ON(display->drm, cpu_transcoder == INVALID_TRANSCODER))
> return false;
>
> if (!intel_display_power_is_enabled(display, POWER_DOMAIN_AUDIO_MMIO))
> @@ -4611,6 +4612,8 @@ intel_ddi_port_sync_transcoders(const struct
> intel_crtc_state *ref_crtc_state,
> if (!crtcs_port_sync_compatible(ref_crtc_state,
> crtc_state))
> continue;
> + if (drm_WARN_ON(display->drm, crtc_state->cpu_transcoder ==
> INVALID_TRANSCODER))
> + continue;
> transcoders |= BIT(crtc_state->cpu_transcoder);
> }
>
> @@ -4649,6 +4652,9 @@ static int intel_ddi_compute_config_late(struct
> intel_encoder *encoder,
> else
> crtc_state->master_transcoder = ffs(port_sync_transcoders) - 1;
>
> + if (drm_WARN_ON(display->drm, crtc_state->cpu_transcoder ==
> INVALID_TRANSCODER))
> + return -EINVAL;
> +
> if (crtc_state->master_transcoder == crtc_state->cpu_transcoder) {
> crtc_state->master_transcoder = INVALID_TRANSCODER;
> crtc_state->sync_mode_slaves_mask =
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> b/drivers/gpu/drm/i915/display/intel_display.c
> index 7491e00e3858..c9d50240d813 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -5855,9 +5855,14 @@ static bool intel_cpu_transcoders_need_modeset(struct
> intel_atomic_state *state,
> {
> const struct intel_crtc_state *new_crtc_state;
> struct intel_crtc *crtc;
> + struct drm_device *drm;
> int i;
>
> + drm = to_intel_display(state)->drm;
Please don't add struct drm_device local variables in display code.
Add display, and use display->drm instead.
BR,
Jani.
> +
> for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
> + if (drm_WARN_ON(drm, new_crtc_state->cpu_transcoder ==
> INVALID_TRANSCODER))
> + continue;
> if (new_crtc_state->hw.enable &&
> transcoders & BIT(new_crtc_state->cpu_transcoder) &&
> intel_crtc_needs_modeset(new_crtc_state))
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 79fd3b8d8b25..402b22423ff2 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -6412,6 +6412,9 @@ static int intel_modeset_affected_transcoders(struct
> intel_atomic_state *state,
> if (!crtc_state->hw.enable)
> continue;
>
> + if (drm_WARN_ON(display->drm, crtc_state->cpu_transcoder ==
> INVALID_TRANSCODER))
> + continue;
> +
> if (!(transcoders & BIT(crtc_state->cpu_transcoder)))
> continue;
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 24f8e60df9ac..f6690130d1cb 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -741,6 +741,9 @@ intel_dp_mst_transcoder_mask(struct intel_atomic_state
> *state,
> if (!crtc_state->hw.active)
> continue;
>
> + if (drm_WARN_ON(display->drm, crtc_state->cpu_transcoder ==
> INVALID_TRANSCODER))
> + continue;
> +
> transcoders |= BIT(crtc_state->cpu_transcoder);
> }
--
Jani Nikula, Intel
