Hi Keith, There is a problem with stopping when changing modes. Below test log root:~> modetest -Mstarfive -c Connectors: id encoder status name size (mm) modes encoders 116 115 connected HDMI-A-1 320x180 51 115 modes: index name refresh (Hz) hdisp hss hse htot vdisp vss vse vtot #0 1280x800 59.91 1280 1328 1360 1440 800 803 809 823 71000 flags: phsync, pvsync; type: preferred, driver #1 1920x1080 60.00 1920 2008 2052 2200 1080 1084 1089 1125 148500 flags: phsync, pvsync; type: driver [...] root:~> modetest -Mstarfive -s 116:#0 -v setting mode 1280x800-59.91Hz on connectors 116, crtc 31 freq: 60.65Hz freq: 59.91Hz freq: 59.91Hz root:~> modetest -Mstarfive -s 116:#1 -v setting mode 1920x1080-60.00Hz on connectors 116, crtc 31 [ 94.535626] rcu: INFO: rcu_sched detected stalls on CPUs/tasks: [ 94.560985] rcu: 1-...0: (20 ticks this GP) idle=c9bc/1/0x4000000000000000 softirq=3869/3871 fqs=1120 [ 94.589532] rcu: (detected by 3, t=5264 jiffies, g=4645, q=63 ncpus=4) [ 94.615335] Task dump for CPU 1: [ 94.637723] task:modetest state:R running task stack:0 pid:407 ppid:397 flags:0x00000008 [ 94.667299] Call Trace: [ 94.689297] [<ffffffff80d1e8fc>] __schedule+0x2a8/0xa52 [ 94.714221] [<ffffffff80d1f100>] schedule+0x5a/0xdc [ 94.738626] [<ffffffff80d25a14>] schedule_timeout+0x220/0x2a6 [ 94.763762] [<ffffffff80d2037a>] wait_for_completion+0xfe/0x126 [ 94.789073] [<ffffffff8002ffe4>] kthread_flush_worker+0x82/0xa0 > -----Original Message----- > From: dri-devel <dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of > Keith Zhao > Sent: Friday, June 2, 2023 4:41 PM > To: dri-devel@xxxxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; linux-riscv@xxxxxxxxxxxxxxxxxxx; linux- > media@xxxxxxxxxxxxxxx; linaro-mm-sig@xxxxxxxxxxxxxxxx > Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@xxxxxxxxxx>; Sumit Semwal > <sumit.semwal@xxxxxxxxxx>; Emil Renner Berthing <kernel@xxxxxxxx>; > Shengyang Chen <shengyang.chen@xxxxxxxxxxxxxxxx>; Conor Dooley > <conor+dt@xxxxxxxxxx>; Albert Ou <aou@xxxxxxxxxxxxxxxxx>; Thomas > Zimmermann <tzimmermann@xxxxxxx>; Jagan Teki <jagan@xxxxxxxxxx>; Rob > Herring <robh+dt@xxxxxxxxxx>; Chris Morgan <macromorgan@xxxxxxxxxxx>; Paul > Walmsley <paul.walmsley@xxxxxxxxxx>; Keith Zhao > <keith.zhao@xxxxxxxxxxxxxxxx>; Bjorn Andersson <andersson@xxxxxxxxxx>; > Changhuang Liang <changhuang.liang@xxxxxxxxxxxxxxxx>; Jack Zhu > <jack.zhu@xxxxxxxxxxxxxxxx>; Palmer Dabbelt <palmer@xxxxxxxxxxx>; Shawn > Guo <shawnguo@xxxxxxxxxx>; christian.koenig@xxxxxxx > Subject: [PATCH 9/9] drm/verisilicon: Add starfive hdmi driver > > Add HDMI dirver for StarFive SoC JH7110. > > Signed-off-by: Keith Zhao <keith.zhao@xxxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/verisilicon/Kconfig | 11 + > drivers/gpu/drm/verisilicon/Makefile | 1 + > drivers/gpu/drm/verisilicon/starfive_hdmi.c | 928 ++++++++++++++++++++ > drivers/gpu/drm/verisilicon/starfive_hdmi.h | 296 +++++++ > drivers/gpu/drm/verisilicon/vs_drv.c | 6 + > drivers/gpu/drm/verisilicon/vs_drv.h | 4 + > 6 files changed, 1246 insertions(+) > create mode 100644 drivers/gpu/drm/verisilicon/starfive_hdmi.c > create mode 100644 drivers/gpu/drm/verisilicon/starfive_hdmi.h [...] > diff --git a/drivers/gpu/drm/verisilicon/starfive_hdmi.c > b/drivers/gpu/drm/verisilicon/starfive_hdmi.c > new file mode 100644 > index 000000000000..128ecca03309 > --- /dev/null > +++ b/drivers/gpu/drm/verisilicon/starfive_hdmi.c > @@ -0,0 +1,928 @@ [...] > +static int starfive_hdmi_setup(struct starfive_hdmi *hdmi, > + struct drm_display_mode *mode) { [...] > + return 0; > +} > + > +static void starfive_hdmi_encoder_mode_set(struct drm_encoder *encoder, > + struct drm_display_mode *mode, > + struct drm_display_mode *adj_mode) { > + struct starfive_hdmi *hdmi = encoder_to_hdmi(encoder); > + > + starfive_hdmi_setup(hdmi, adj_mode); When starfive_hdmi_setup runs here, when changing the mode, a problem occurs because try to write a value to reg in a state that is not resumed after suspend. > + > + memcpy(&hdmi->previous_mode, adj_mode, sizeof(hdmi- > >previous_mode)); } > + > +static void starfive_hdmi_encoder_enable(struct drm_encoder *encoder) { > + struct starfive_hdmi *hdmi = encoder_to_hdmi(encoder); > + > + pm_runtime_get_sync(hdmi->dev); So if move the call point of starfive_hdmi_setup here, it works normally. > +} Best regards, Hoegeun