On Sat, Feb 14, 2026 at 01:02:59AM +0200, Dmitry Baryshkov wrote:
> This reverts commit 42f62cd79578 ("drm/msm/dpu: try reserving the
> DSPP-less LM first"). It seems on later DPUs using higher LMs require
> some additional setup or conflicts with the hardware defaults. Val (and
> other developers) reported blue screen on Hamoa (X1E80100) laptops.
> Revert the offending commit until we understand, what is the issue.
>
> Fixes: 42f62cd79578 ("drm/msm/dpu: try reserving the DSPP-less LM first")
> Reported-by: Val Packett <[email protected]>
> Closes:
> https://lore.kernel.org/r/[email protected]
> Signed-off-by: Dmitry Baryshkov <[email protected]>
Tested-by: Manivannan Sadhasivam <[email protected]> # T14s
- Mani
> ---
> drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c | 52
> +++++++++-------------------------
> 1 file changed, 14 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> index 451a4fcf3e65..7e77d88f8959 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> @@ -350,26 +350,28 @@ static bool
> _dpu_rm_check_lm_and_get_connected_blks(struct dpu_rm *rm,
> return true;
> }
>
> -static bool dpu_rm_find_lms(struct dpu_rm *rm,
> - struct dpu_global_state *global_state,
> - uint32_t crtc_id, bool skip_dspp,
> - struct msm_display_topology *topology,
> - int *lm_idx, int *pp_idx, int *dspp_idx)
> +static int _dpu_rm_reserve_lms(struct dpu_rm *rm,
> + struct dpu_global_state *global_state,
> + uint32_t crtc_id,
> + struct msm_display_topology *topology)
>
> {
> + int lm_idx[MAX_BLOCKS];
> + int pp_idx[MAX_BLOCKS];
> + int dspp_idx[MAX_BLOCKS] = {0};
> int i, lm_count = 0;
>
> + if (!topology->num_lm) {
> + DPU_ERROR("zero LMs in topology\n");
> + return -EINVAL;
> + }
> +
> /* Find a primary mixer */
> for (i = 0; i < ARRAY_SIZE(rm->mixer_blks) &&
> lm_count < topology->num_lm; i++) {
> if (!rm->mixer_blks[i])
> continue;
>
> - if (skip_dspp && to_dpu_hw_mixer(rm->mixer_blks[i])->cap->dspp)
> {
> - DPU_DEBUG("Skipping LM_%d, skipping LMs with DSPPs\n",
> i);
> - continue;
> - }
> -
> /*
> * Reset lm_count to an even index. This will drop the previous
> * primary mixer if failed to find its peer.
> @@ -408,38 +410,12 @@ static bool dpu_rm_find_lms(struct dpu_rm *rm,
> }
> }
>
> - return lm_count == topology->num_lm;
> -}
> -
> -static int _dpu_rm_reserve_lms(struct dpu_rm *rm,
> - struct dpu_global_state *global_state,
> - uint32_t crtc_id,
> - struct msm_display_topology *topology)
> -
> -{
> - int lm_idx[MAX_BLOCKS];
> - int pp_idx[MAX_BLOCKS];
> - int dspp_idx[MAX_BLOCKS] = {0};
> - int i;
> - bool found;
> -
> - if (!topology->num_lm) {
> - DPU_ERROR("zero LMs in topology\n");
> - return -EINVAL;
> - }
> -
> - /* Try using non-DSPP LM blocks first */
> - found = dpu_rm_find_lms(rm, global_state, crtc_id, !topology->num_dspp,
> - topology, lm_idx, pp_idx, dspp_idx);
> - if (!found && !topology->num_dspp)
> - found = dpu_rm_find_lms(rm, global_state, crtc_id, false,
> - topology, lm_idx, pp_idx, dspp_idx);
> - if (!found) {
> + if (lm_count != topology->num_lm) {
> DPU_DEBUG("unable to find appropriate mixers\n");
> return -ENAVAIL;
> }
>
> - for (i = 0; i < topology->num_lm; i++) {
> + for (i = 0; i < lm_count; i++) {
> global_state->mixer_to_crtc_id[lm_idx[i]] = crtc_id;
> global_state->pingpong_to_crtc_id[pp_idx[i]] = crtc_id;
> global_state->dspp_to_crtc_id[dspp_idx[i]] =
>
> ---
> base-commit: 50c4a49f7292b33b454ea1a16c4f77d6965405dc
> change-id: 20260214-revert-dspp-less-8426dee24b92
>
> Best regards,
> --
> With best wishes
> Dmitry
>
--
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