[PATCH v3 0/5] powervr: MT8173 GPU support
Chen-Yu Tsai
wenst at chromium.org
Mon Jul 27 23:37:22 PDT 2026
On Mon, Jul 27, 2026 at 11:49 PM YoungJoon Lee <getfeus at gmail.com> wrote:
>
> Hello,
>
> I tested patches 1/5 through 5/5 from the MT8173 PowerVR v3 series on
> an Acer Chromebook R13 (Google Elm), which uses an MT8173 SoC and a
> PowerVR Rogue GX6250 GPU with BVNC 4.40.2.51.
>
> For clarity, I applied the five actual patches numbered 1/5 through
> 5/5. The 0/5 cover letter itself was not applied.
>
> Kernel:
> Linux 7.1.3-stb-cbm-pvr-v3
Please at least try linux-next. There's around 30 patches for powervr
between v7.1 and next-20260727, 15 if you count from v7.1 to v7.2-rc1.
> Relevant kernel configuration:
> CONFIG_DRM_POWERVR=m
> CONFIG_COMMON_CLK_MT8173_MFGTOP=y
>
> Kernel command line:
> powervr.exp_hw_support=1
>
> Firmware:
> powervr/rogue_4.40.2.51_v1.fw
>
> The driver probes successfully, loads the firmware, and initializes the
> DRM device:
>
> [ 6.110569] powervr 13000000.gpu:
> [drm] Running on unknown hardware; expect issues.
> [ 6.117454] powervr 13000000.gpu:
> [drm] loaded firmware
> powervr/rogue_4.40.2.51_v1.fw
> [ 6.118010] powervr 13000000.gpu:
> [drm] FW version v1.0 (build 6476056 OS)
> [ 6.122992] [drm] Initialized powervr 1.0.0
> for 13000000.gpu on minor 1
>
> The following DRM device nodes are created:
>
> /dev/dri/card0
> /dev/dri/card1
> /dev/dri/renderD128
>
> However, on a clean boot, without manually running vulkaninfo, vkcube,
> or another Vulkan application, the driver reports that the GPU has been
> lost approximately six seconds after DRM initialization:
>
> [ 12.084078] powervr 13000000.gpu:
> [drm] *ERROR* GPU device lost
>
> The relevant boot sequence is therefore:
>
> [ 6.110569] PowerVR probe begins
> [ 6.117454] Firmware is loaded
> [ 6.118010] Firmware version is reported
> [ 6.122992] DRM initialization completes
> [ 12.084078] GPU device lost
>
> The unused-regulator shutdown occurs considerably later:
>
> [ 31.712124] vgpu: disabling
>
> Therefore, the later "vgpu: disabling" message does not appear to be
> the immediate cause of the device loss. The GPU is reported lost about
> 20 seconds before that regulator shutdown message.
>
> After the failure, regulator_summary reports:
>
> vgpu 0 0 0 normal 1000mV 0mA 700mV 1350mV
This is unrelated. This regulator output is _really_ unused. "vgpu" is
just the default name on the PMIC.
> This output was collected after the GPU had already been reported lost,
> so I do not know whether the regulator state was different during probe
> or immediately before the failure.
>
> The PowerVR-related clocks appear enabled in clk_summary:
>
> mfg_26m 26000000 Hz
>
> mem_mfg_in_sel
> rate: 455000000 Hz
> enable: 1
> prepare: 1
>
> mfg_mem
> rate: 455000000 Hz
> enable: 1
> prepare: 1
> consumer: 13000000.gpu
> clock name: mem
>
> mfg_sel
> rate: 455000000 Hz
> enable: 1
> prepare: 1
>
> mfg_g3d
> rate: 455000000 Hz
> enable: 1
> prepare: 1
> consumer: 13000000.gpu
> clock name: core
>
> axi_mfg_in_sel
> rate: 208000000 Hz
> enable: 2
> prepare: 2
> consumer: power-domain at 7
>
> mfg_axi
> rate: 208000000 Hz
> enable: 1
> prepare: 1
> consumer: 13000000.gpu
> clock name: sys
>
> I also installed Mesa 26.1.5 and vulkan-powervr 26.1.5 and tested the
> Vulkan ICD with:
>
> PVR_I_WANT_A_BROKEN_VULKAN_DRIVER=1 \
> VK_DRIVER_FILES=/usr/share/vulkan/icd.d/powervr_mesa_icd.json \
> vulkaninfo --summary
>
> The PowerVR ICD was found and loaded. Before hanging, Mesa printed:
>
> WARNING: powervr is not a conformant Vulkan implementation,
> testing use only.
>
> FINISHME: Missing reset support for brn51764
> FINISHME: Missing reset support for brn58839
> FINISHME: Missing support for brn62269
> FINISHME: Devices without tpu_border_colour_enhanced require entries
> for compressed formats to be stored in the table
> pre-compressed.
>
> The vulkaninfo process then remained in uninterruptible sleep:
>
> PID STAT WCHAN COMMAND
> 3244 Dl+ synchronize_srcu vulkaninfo --summary
>
> It could not be terminated normally while in that state, and a reboot
> was required.
>
> However, the clean-boot log shows that "GPU device lost" occurs even
> without starting vulkaninfo manually. The vulkaninfo hang may therefore
> be a consequence of the GPU already being in the lost state, rather than
> the original cause of the failure.
>
> At this point, the following parts appear to work:
>
> - MT8173 GPU device-tree node probing
> - MFGTOP clock registration
> - PowerVR kernel module probing
> - Firmware loading
> - Firmware version reporting
> - DRM device initialization
> - Creation of card1 and renderD128
>
> The remaining problem is that the GPU becomes lost approximately six
> seconds after initialization.
Sorry. I'm not seeing this on my device. I'm running the patches on
top of next-20260727 this round.
ChenYu
> Could this be related to an interrupt not being delivered, firmware
> heartbeat handling, reset sequencing, runtime PM, a missing regulator
> consumer relationship, or another MT8173-specific power-domain
> requirement?
>
> Please let me know which additional kernel debug options, DRM debug
> settings, tracepoints, interrupt statistics, register dumps, or test
> patches would be useful. I have physical access to the device and can
> build and test further kernel changes.
>
> Thank you for working on MT8173 support.
>
> Best regards,
> YoungJoon Lee
>
> 2026年7月27日(月) 18:16 Chen-Yu Tsai <wenst at chromium.org>:
> >
> > Hi everyone,
> >
> > This is v3 of my MT8173 PowerVR GPU support series.
> >
> > I got another inquiry on the status of this patch series, so I thought
> > I'd dig it out, fix all the issues and send another version.
> >
> > This time around Mesa was ready for basic testing, using both vulkanmark
> > and glmark2-es2-drm (with Zink). Details below.
> >
> > Changes since v2 (all in the clk driver patch):
> > - Made COMMON_CLK_MT8173_MFGTOP depend on PM
> > - Needed since the driver implements PM domains using the generic PM
> > domain library, which also depends on PM
> > - Fixes build breakage (kernel test robot)
> > - Fixed "RST_DELAY_CNT" name (Brian)
> > - Dropped unused mfg_desc (Brian)
> > - Added check of clk_prepare_enable()'s return value in
> > clk_mt8173_mfgtop_power_on() (Brian)
> > - Saved error value for return in IS_ERR(data->clk_26m) branch
> > (Dan Carpenter / kernel test robot w/ smatch)
> >
> > Changes since v1:
> > - Adapted to changed DT bindings
> > - Dropped driver change
> > - Use same power domain for "a" and "b" GPU power domains
> >
> >
> > This series enables the PowerVR GPU found in the MT8173 SoC, found in
> > some Chromebooks.
> >
> > This version is different from the initial powervr driver submission [1]
> > in that it splits out the GPU glue layer support out of the powervr
> > driver and into a separate clock and power domain driver. The glue code
> > is otherwise the same, and also the same as found in the ChromeOS
> > kernels, with some extra comments and macro names added where possible.
> >
> > Patch 1 adds a binding for the glue layer, called mfgtop. The glue layer
> > contains clock and power controls for the GPU.
> >
> > Patch 2 adds a driver for the glue layer, implemented as a clock driver
> > that also provides power domains.
> >
> > Patch 3 adds an entry for the MT8173 GPU and 6XT series to the PowerVR
> > binding.
> >
> > Patch 4 corrects the clock for the GPU (called MFG) power domain.
> >
> > Patch 5 adds device nodes for the GPU and glue layer to the MT8173 dtsi
> > file.
> >
> > The kernel driver successfully probes the hardware and loads the
> > "rogue_4.40.2.51_v1.fw" firmware provided by Imagination Technologies [2].
> > The "exp_hw_support" module parameter needs to be set for the driver to
> > probe successfully.
> >
> > This was tested with Mesa 26.1.5 from Debian Forky. With this version
> > vkmark and glmark2-es2 (over Zink) both run fine. Mesa spits out a bunch
> > of warnings since the GX6250 core is not officially supported.
> >
> > # PVR_I_WANT_A_BROKEN_VULKAN_DRIVER=1 vkmark
> > WARNING: powervr is not a conformant Vulkan implementation, testing use only.
> > WARNING: powervr is not a conformant Vulkan implementation, testing use only.
> > MESA: warning: ../src/imagination/vulkan/pvr_arch_job_context.c:73: FINISHME: Missing reset support for brn51764
> > MESA: warning: ../src/imagination/vulkan/pvr_arch_job_context.c:76: FINISHME: Missing reset support for brn58839
> > MESA: warning: ../src/imagination/vulkan/pvr_arch_job_context.c:523: FINISHME: Missing support for brn62269
> > MESA: warning: ../src/imagination/vulkan/pvr_arch_border.c:244: FINISHME: Devices without tpu_border_colour_enhanced require entries for compressed formats to be stored in the table pre-compressed.
> > WARNING: powervr is not a conformant Vulkan implementation, testing use only.
> > =======================================================
> > vkmark 2025.01
> > =======================================================
> > Vendor ID: 0x1010
> > Device ID: 0x6250
> > Device Name: PowerVR Rogue GX6250
> > Driver Version: 109056005
> > Device UUID: d04cd6f3a25fd4900f89c151bccfdfcf
> > =======================================================
> > [vertex] device-local=true: FPS: 251 FrameTime: 3.984 ms
> > [vertex] device-local=false: FPS: 220 FrameTime: 4.545 ms
> > [texture] anisotropy=0:^C FPS: 223 FrameTime: 4.484 ms
> > =======================================================
> > vkmark Score: 231
> > =======================================================
> >
> > # PVR_I_WANT_A_BROKEN_VULKAN_DRIVER=1 glmark2-es2-drm
> > WARNING: powervr is not a conformant Vulkan implementation, testing use only.
> > MESA: warning: ../src/imagination/vulkan/pvr_arch_job_context.c:73: FINISHME: Missing reset support for brn51764
> > MESA: warning: ../src/imagination/vulkan/pvr_arch_job_context.c:76: FINISHME: Missing reset support for brn58839
> > MESA: warning: ../src/imagination/vulkan/pvr_arch_job_context.c:523: FINISHME: Missing support for brn62269
> > MESA: warning: ../src/imagination/vulkan/pvr_arch_border.c:244: FINISHME: Devices without tpu_border_colour_enhanced require entries for compressed formats to be stored in the table pre-compressed.
> > Warning: DRM_CAP_ASYNC_PAGE_FLIP not supported, falling back to 'mailbox' mode for SwapInterval(0).
> > =======================================================
> > glmark2 2023.01
> > =======================================================
> > OpenGL Information
> > GL_VENDOR: Mesa
> > GL_RENDERER: zink Vulkan 1.2(PowerVR Rogue GX6250 (IMAGINATION_OPEN_SOURCE_MESA))
> > GL_VERSION: OpenGL ES 2.0 Mesa 26.1.5-1
> > Surface Config: buf=32 r=8 g=8 b=8 a=8 depth=24 stencil=0 samples=0
> > Surface Size: 1366x768 fullscreen
> > =======================================================
> > [build] use-vbo=false: FPS: 49 FrameTime: 20.473 ms
> > [build] use-vbo=true: FPS: 45 FrameTime: 22.660 ms
> > [texture] texture-filter=nearest: FPS: 45 FrameTime: 22.642 ms
> > [texture] texture-filter=linear:^C FPS: 50 FrameTime: 20.172 ms
> > =======================================================
> > glmark2 Score: 46
> > =======================================================
> >
> >
> > Please have a look.
> >
> > Thanks
> > ChenYu
> >
> > [1] https://lore.kernel.org/dri-devel/20220815165156.118212-2-sarah.walker@imgtec.com/
> > [2] https://gitlab.freedesktop.org/imagination/linux-firmware/-/tree/powervr
> >
> > Chen-Yu Tsai (5):
> > dt-bindings: clock: mediatek: Add mt8173 mfgtop
> > clk: mediatek: Add mt8173-mfgtop driver
> > dt-bindings: gpu: powervr-rogue: Add MediaTek MT8173 GPU
> > arm64: dts: mediatek: mt8173: Fix MFG_ASYNC power domain clock
> > arm64: dts: mediatek: mt8173: Add GPU device nodes
> >
> > .../clock/mediatek,mt8173-mfgtop.yaml | 70 +++++
> > .../bindings/gpu/img,powervr-rogue.yaml | 1 +
> > arch/arm64/boot/dts/mediatek/mt8173.dtsi | 33 ++-
> > drivers/clk/mediatek/Kconfig | 10 +
> > drivers/clk/mediatek/Makefile | 1 +
> > drivers/clk/mediatek/clk-mt8173-mfgtop.c | 241 ++++++++++++++++++
> > include/dt-bindings/clock/mt8173-clk.h | 7 +
> > 7 files changed, 362 insertions(+), 1 deletion(-)
> > create mode 100644 Documentation/devicetree/bindings/clock/mediatek,mt8173-mfgtop.yaml
> > create mode 100644 drivers/clk/mediatek/clk-mt8173-mfgtop.c
> >
> > --
> > 2.55.0.229.g6434b31f56-goog
> >
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