[PATCH v7 00/18] Synopsys DisplayPort Controller improvements for Rockchip platforms
Sebastian Reichel
sebastian.reichel at collabora.com
Tue Jul 28 10:40:36 PDT 2026
This patch series updates the Synopsys Designware DisplayPort bridge
together with the only existing user: The Rockchip RK3576/RK3588:
1. Follow-up bridges (PHY, USB-C connector)
This is needed to get USB-C DP AltMode working; I've followed
the Qualcomm driver as reference
2. Runtime PM
The initial driver has been upstreamed without RPM; add it to
avoid wasting power when nothing is plugged
3. Audio
The initial driver has been upstreamed without audio support;
this adds all missing bits for audio with single stream transport
To properly make use of the bridge code the following USBDP PHY series
is also needed:
https://lore.kernel.org/all/20260714-rockchip-usbdp-cleanup-v13-0-6cb3e769d4c5@collabora.com/
This series can be applied without the USBDP side. In that case USB-C
support won't work as the mainline USBDP side does not register as a
DRM bridge. As upstream DT binding for USBDP does not yet support
proper ports, no such board should be upstream.
Boards using the DP controller for native DP connectors (or HDMI
bridges), currently directly link to the connector/hdmi bridge. These
are not affected by the USBDP changes and should keep working in any
case. The difference is, that this series the DRM side is aware of the
link. I don't have any of those boards, so this code path is untested.
I added a dedicated bridge callback for out-of-band hotplug events,
which is separate from the hotplug_notify. I have a feeling, that
there might be a better solution, but haven't found it. Please comment.
Changes in v7:
- Link to v6: https://lore.kernel.org/r/20260724-synopsys-dw-dp-improvements-v6-0-041d99a19c4e@collabora.com
- Move drm_bridge_add() to probe and only attach it in the bind
function, as the object is re-used and not fully cleared by
drm_bridge_remove (Sashiko)
- Add a new patch resetting the DP AUX sub-controller on message
timeout to have decent error recovery (Sashiko)
- Fix dp_dp_rockchip_get_vo_grf -> dw_dp_rockchip_get_vo_grf (Sashiko)
- Introduce pm_active in the PM runtime patch, to early exit
on atomic_disable when atomic_enable failed to get runtime
PM enabled (Sashiko)
- Introduce drm_bound in the PM runtime patch, which is (un)set
when the driver is bound to a DRM encoder and used to enable
IRQ enabling in the runtime PM handlers. This in turn protects
the system of potential spurious interrupts. (Sashiko)
- In the audio patch, fix support for hotplug with a running
audio stream. (Sashiko)
- To avoid further blowing up the series, I've decided not to
act on these "pre-existing" issues reported by Sashiko. I
think it makes sense to handle them separately:
* Short HPD and Long HPD events share a single boolean state
variable, causing critical hot plug events to be lost if
interrupts arrive in quick succession.
* DP AUX lifetime complains (registered too early / unregistered
too late); reported multiple times
* The driver fails to support DP AUX short reads, incorrectly
rejecting them with -EBUSY instead of returning the number
of bytes successfully transferred, which breaks I2C-over-AUX.
- Collected Reviewed-by from Krzysztof Kozlowski on the
DT binding patch
Changes in v6:
- Link to v5: https://lore.kernel.org/r/20260724-synopsys-dw-dp-improvements-v5-0-9445c2e87441@collabora.com
- Fix overlong commit message in mutex patch
- Update MEDIA_BUS_FMT_FIXED patch, to use input format as output format
when output format is MEDIA_BUS_FMT_FIXED (Sashiko)
- Drop patch moving dw_dp_bridge_atomic_get_output_bus_fmts (no longer
needed)
- Reword the comment about platforms other than RK3576 and RK3588
shouldn't get the VO GRF from the USBDP to make it more obvious
that no such platform exist at the moment and thus the alternative
path will not be implemented at this point in time (Sashiko)
- Update the runtime PM code to have much better error handling
as well as support for platforms not using runtime PM (Sashiko)
- Update the runtime PM code to keep the device suspended when
probed, but unbound as a nice side effect
- Fix error handling for dw_dp_audio_infoframe_send() in audio
patch (Sashiko)
- Fix typo in sample width check in audio patch (Sashiko)
- Improve cleanup of SDP in audio patch (Sashiko)
Changes in v5:
- Link to v4: https://lore.kernel.org/r/20260721-synopsys-dw-dp-improvements-v4-0-f0f4a4ede712@collabora.com
- Add new patch to cancel pending HPD work on unbind (Sashiko)
- Add new patch to add missing mutex cleanups on module removal (Sashiko)
- Add new patch moving dw_dp_bridge_atomic_get_output_bus_fmts
- Update MEDIA_BUS_FMT_FIXED patch to avoid fixed RGB888 format
and instead use whatever works for the negotiated bandwidth (Sashiko)
- Add more error checking for runtime PM patches (Sashiko)
- Ensure runtime PM is held in interrupt handler (Sashiko)
- Fix usbc_mode logic inversion for runtime PM in unbind (Sashiko)
- Move sleep for HPD_HOT_PLUG from hotplug handler to runtime
resume function; no need to sleep when runtime PM is kept
active and runtime PM resume is a slow operation anyways. (Sashiko)
- Add new patch to protect sdp_reg_bank from concurrent access (Sashiko)
- Add new patch to use regmap_set_bits in dw_dp_send_sdp()
- Update DT binding patch to be all about the selected solution and
mention the ABI break
- Clear SDP in the audio patch on unprepare (Sashiko)
- Add a comment, that only 1,2 or 8 channels are supported (Sashiko)
- Error out on unsupported sample_width (Sashiko)
- Fix missing error check for clock enable (Sashiko)
Changes in PATCHv4:
- Link to v3: https://lore.kernel.org/all/20260612-synopsys-dw-dp-improvements-v3-0-dc61e6352508@collabora.com/
- Drop "Simplify driver data setting" (effectively reverted later on)
- Add "Fix incorrect resource lifetimes in bind callback", which
affects all following patches quite a bit (Sashiko)
- Update "Add follow-up bridge support" to mention that fatal errors
are fine (Sashiko)
- Update "Add out-of-band HPD notify handler" to use
drm_for_each_bridge_in_chain() instead of
drm_for_each_bridge_in_chain_scoped() required after rebase to
latest drm-misc-next
- Add 100ms sleep in hpd detect functions after runtime resume in the
"Add Runtime PM support" patch (Andy Yan)
- Keep runtime PM enabled if DP is used without USB-C to avoid missing
HPD signals in "Add Runtime PM support" patch (Andy Yan)
- Update patch description of DT binding patch and drop RFC tag
- Use pm_runtime_resume_and_get() in the audio startup function, which
allows easy error handling (Sashiko)
- Avoid updating audio_interface in the audio prepare function when
an error related early exit happens (Sashiko)
- Add error handling for clock prepare calls in audio prepare function
(Sashiko)
Changes in PATCHv3:
- Link to v2: https://lore.kernel.org/r/20260501-synopsys-dw-dp-improvements-v2-0-d7e7f6bac77f@collabora.com
- Collect Reviewed-by on "Simplify driver data setting" patch (Andy Yan)
- Use of_drm_get_bridge_by_endpoint instead of devm_drm_of_get_bridge (Luca Ceresoli)
- Use FIELD_PREP_WM16 instead of FIELD_PREP_WM16_CONST (Chaoyi Chen)
- Rebase to latest drm-misc-next (Dropped Cristian's patches)
Changes in PATCHv2:
* Link to v1: https://lore.kernel.org/r/20260326-synopsys-dw-dp-improvements-v1-0-501849162290@collabora.com
* rebased to latest drm-misc-next
* prepended the Patches from Cristian's cleanup series, as they also
needed a rebase and should be merged first
https://lore.kernel.org/dri-devel/20260327-drm-rk-fixes-v3-0-fd2e6900c08c@collabora.com/
* fix issue with the audio stream (un)prepare handling in last patch
Signed-off-by: Sebastian Reichel <sebastian.reichel at collabora.com>
---
Sebastian Reichel (18):
drm/bridge: synopsys: dw-dp: Fix incorrect resource lifetimes in bind callback
drm/bridge: synopsys: dw-dp: Cancel pending HPD work on unbind
drm/bridge: synopsys: dw-dp: Add missing mutex cleanups on module removal
drm/bridge: synopsys: dw-dp: Add missing reinit_completion
drm/bridge: synopsys: dw-dp: Reset AUX channel on transfer timeout
drm/bridge: synopsys: dw-dp: Free output_fmts when none are valid
drm/bridge: synopsys: dw-dp: Support MEDIA_BUS_FMT_FIXED
drm/bridge: synopsys: dw-dp: Add follow-up bridge support
drm/bridge: Add out-of-band HPD notify handler
drm/bridge: synopsys: dw-dp: Support software triggered OOB HPD
drm/rockchip: dw_dp: Implement out-of-band HPD handling
drm/bridge: synopsys: dw-dp: Add Runtime PM support
drm/rockchip: dw_dp: Add runtime PM support
drm/bridge: synopsys: dw-dp: Protect sdp_reg_bank from concurrent access
drm/bridge: synopsys: dw-dp: Use regmap_set_bits in dw_dp_send_sdp
dt-bindings: display: rockchip: dw-dp: Fix sound DAI cells
drm/bridge: synopsys: dw-dp: Clear only enabled SDPs on atomic disable
drm/bridge: synopsys: dw-dp: Add audio support
.../bindings/display/rockchip/rockchip,dw-dp.yaml | 9 +-
drivers/gpu/drm/bridge/synopsys/dw-dp.c | 684 ++++++++++++++++++---
drivers/gpu/drm/display/drm_bridge_connector.c | 6 +
drivers/gpu/drm/rockchip/dw_dp-rockchip.c | 219 ++++++-
include/drm/bridge/dw_dp.h | 11 +-
include/drm/drm_bridge.h | 14 +
6 files changed, 840 insertions(+), 103 deletions(-)
---
base-commit: df0311845915442ab75d03ee89fb443b444c1370
change-id: 20260325-synopsys-dw-dp-improvements-7da2e98df1dd
Best regards,
--
Sebastian Reichel <sebastian.reichel at collabora.com>
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