[v3,0/3] drm/msm: Initial fixes for DUALPIPE (+DSC) topology

Message

Marijn Suijten Feb. 17, 2025, 11:17 a.m. UTC

This series covers a step-up towards supporting the DUALPIPE DSC
topology, also known as 2:2:2 topology (on active-CTL hardware).  It
involves 2 layer mixers, 2 DSC compression encoders, and 2 interfaces
(on DSI, this is called bonded-DSI) where bandwidth constraints (e.g. 4k
panels at 120Hz) require two interfaces to transmit pixel data.

Enabling this topology will be hard(er) than downstream as hacking a
layout type in DTS won't be describing the hardware, but "dynamically"
determining it at runtime may pose some of a challenge that is left to a
future series.  Such changes will also involve the 1:1:1 topology needed
for constrained hardware like the Fairphone 5 on SC7280 with access to
only one DSC encoder and thus ruled out of the current 2:2:1 topology.

Likewise, the patches and discussions around improving active-CTL
configuration to support bonded interfaces (that share a single CTL
block) are still in full swing and hence elided from this series, apart
from one patch to fix the ACTIVE_DSC register coding to support updates,
so that it is not forgotten about.

This issue and successful resolution of all the problems is discussed
and demonstrated in https://gitlab.freedesktop.org/drm/msm/-/issues/41.

Signed-off-by: Marijn Suijten <[e-mail]>
---
Changes in v3:
- Removed start of multiline comment inside another comment
  (editor detritus from merging two comments in v2);
- Inserted empty newline after the start of multi-line comments (per
  kernel coding style).
- Link to v2: https://lore.kernel.org/r/[e-mail]

Changes in v2:
- Dropped patches that were applied;
- dsi_mgr_setup_components() now sets both the usecase and phy_mode
  prior to calling msm_dsi_host_register(), and for non-bonded too;
- Added patch to remove a forced num_intf = 1 when DSC is enabled;
- Reworked hdisplay/2 "fix" when calculating "DSC timing" to instead use
  dsc->slice_count, allowing us to remove msm_dsc_get_slices_per_intf()
  entirely;
- Link to v1: https://lore.kernel.org/r/[e-mail]

Depends on:
- https://lore.kernel.org/linux-arm-msm/[e-mail]/
  (only to prevent conflicts with the patch that removes a hardcoded
   num_intf = 1;).

---
Marijn Suijten (3):
      drm/msm/dsi: Use existing per-interface slice count in DSC timing
      drm/msm/dsi: Set PHY usescase (and mode) before registering DSI host
      drm/msm/dpu: Remove arbitrary limit of 1 interface in DSC topology

 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c |  7 ++++---
 drivers/gpu/drm/msm/dsi/dsi_host.c          |  8 ++++----
 drivers/gpu/drm/msm/dsi/dsi_manager.c       | 32 +++++++++++++++++++----------
 drivers/gpu/drm/msm/msm_dsc_helper.h        | 11 ----------
 4 files changed, 29 insertions(+), 29 deletions(-)
---
base-commit: ed58d103e6da15a442ff87567898768dc3a66987
change-id: 20240416-drm-msm-initial-dualpipe-dsc-fixes-3f0715b03bf4
prerequisite-message-id: <[e-mail]>
prerequisite-patch-id: 9ed44ae089b173f452a6603e6739b0b3bf2d9274

Best regards,