Re: [PATCH v2 00/16] drm/msm: Support for Inter Frame Power Collapse (IFPC) feature

[Neil Armstrong <neil.armstrong@linaro.org>]

On 08/09/2025 10:26, Akhil P Oommen wrote:
> This patch series introduces the IFPC feature to the DRM-MSM driver for
> Adreno GPUs. IFPC enables GMU to quickly transition GPU into a low power
> state when idle and quickly resume gpu to active state upon workload
> submission, hence the name 'Inter Frame Power Collapse'. Since the KMD is
> unaware of these transitions, it must perform a handshake with the
> hardware (eg: fenced_write, OOB signaling etc) before accessing registers
> in the GX power domain.
> 
> Initial patches address a few existing issues that were not exposed in the
> absence of IFPC. Rest of the patches are additional changes required for
> IFPC. This series adds the necessary restore register list for X1-85/A750
> GPUs and enables IFPC support for them.
> 
> To: Rob Clark <robin.clark@oss.qualcomm.com>
> To: Sean Paul <sean@poorly.run>
> To: Konrad Dybcio <konradybcio@kernel.org>
> To: Dmitry Baryshkov <lumag@kernel.org>
> To: Abhinav Kumar <abhinav.kumar@linux.dev>
> To: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
> To: Marijn Suijten <marijn.suijten@somainline.org>
> To: David Airlie <airlied@gmail.com>
> To: Simona Vetter <simona@ffwll.ch>
> To: Antonino Maniscalco <antomani103@gmail.com>
> To: Neil Armstrong <neil.armstrong@linaro.org>
> Cc: linux-arm-msm@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: freedreno@lists.freedesktop.org
> Cc: linux-kernel@vger.kernel.org
> Cc: Antonino Maniscalco <antomani103@gmail.com>
> Cc: Neil Armstrong <neil.armstrong@linaro.org>
> 
> Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
> ---
> Changes in v2:
> - Elaborate commit text and add Fixes tags (Dmitry/Konrad)
> - Document GMU_IDLE_STATE_RESERVED (Konrad)
> - Add a memory barrier in fenced_write
> - Move an error print in fenced_write to after polling
> - %s/set_keepalive_vote/a6xx[gpu|preempt]_keepalive_vote (Dmitry)
> - Add an "unlikely()" to read_gmu_ao_counter() (Konrad/Rob)
> - Define IFPC_LONG_HYST to document a magic number
> - Add a new patch to enable IFPC on A750 GPU (Neil/Antonino)
> - Drop patch 12 & 17 from v1 revision
> - Link to v1: https://lore.kernel.org/r/20250720-ifpc-support-v1-0-9347aa5bcbd6@oss.qualcomm.com
> 
> ---
> Akhil P Oommen (16):
>        drm/msm: Update GMU register xml
>        drm/msm: a6xx: Fix gx_is_on check for a7x family
>        drm/msm/a6xx: Poll additional DRV status
>        drm/msm/a6xx: Fix PDC sleep sequence
>        drm/msm: a6xx: Refactor a6xx_sptprac_enable()
>        drm/msm: Add an ftrace for gpu register access
>        drm/msm/adreno: Add fenced regwrite support
>        drm/msm/a6xx: Set Keep-alive votes to block IFPC
>        drm/msm/a6xx: Switch to GMU AO counter
>        drm/msm/a6xx: Poll AHB fence status in GPU IRQ handler
>        drm/msm: Add support for IFPC
>        drm/msm/a6xx: Fix hangcheck for IFPC
>        drm/msm/adreno: Disable IFPC when sysprof is active
>        drm/msm/a6xx: Make crashstate capture IFPC safe
>        drm/msm/a6xx: Enable IFPC on Adreno X1-85
>        drm/msm/a6xx: Enable IFPC on A750 GPU
> 
>   drivers/gpu/drm/msm/adreno/a6xx_catalog.c         |  71 ++++++-
>   drivers/gpu/drm/msm/adreno/a6xx_gmu.c             | 105 ++++++++--
>   drivers/gpu/drm/msm/adreno/a6xx_gmu.h             |  14 ++
>   drivers/gpu/drm/msm/adreno/a6xx_gpu.c             | 221 ++++++++++++++++++----
>   drivers/gpu/drm/msm/adreno/a6xx_gpu.h             |   3 +
>   drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c       |  10 +-
>   drivers/gpu/drm/msm/adreno/a6xx_hfi.c             |  34 +++-
>   drivers/gpu/drm/msm/adreno/a6xx_preempt.c         |  40 +++-
>   drivers/gpu/drm/msm/adreno/adreno_gpu.h           |   1 +
>   drivers/gpu/drm/msm/msm_gpu.h                     |   9 +
>   drivers/gpu/drm/msm/msm_gpu_trace.h               |  12 ++
>   drivers/gpu/drm/msm/msm_submitqueue.c             |   4 +
>   drivers/gpu/drm/msm/registers/adreno/a6xx_gmu.xml |  11 ++
>   13 files changed, 459 insertions(+), 76 deletions(-)
> ---
> base-commit: 5cc61f86dff464a63b6a6e4758f26557fda4d494
> change-id: 20241216-ifpc-support-3b80167b3532
> 
> Best regards,

Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-HDK

Thanks,
Neil