RE: [PATCH 9/9] drm/verisilicon: Add starfive hdmi driver

["Hoegeun Kwon" <hoegeun.kwon@samsung.com>]

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@lists.freedesktop.org> On Behalf Of
> Keith Zhao
> Sent: Friday, June 2, 2023 4:41 PM
> To: dri-devel@lists.freedesktop.org; devicetree@vger.kernel.org; linux-
> kernel@vger.kernel.org; linux-riscv@lists.infradead.org; linux-
> media@vger.kernel.org; linaro-mm-sig@lists.linaro.org
> Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>; Sumit Semwal
> <sumit.semwal@linaro.org>; Emil Renner Berthing <kernel@esmil.dk>;
> Shengyang Chen <shengyang.chen@starfivetech.com>; Conor Dooley
> <conor+dt@kernel.org>; Albert Ou <aou@eecs.berkeley.edu>; Thomas
> Zimmermann <tzimmermann@suse.de>; Jagan Teki <jagan@edgeble.ai>; Rob
> Herring <robh+dt@kernel.org>; Chris Morgan <macromorgan@hotmail.com>; Paul
> Walmsley <paul.walmsley@sifive.com>; Keith Zhao
> <keith.zhao@starfivetech.com>; Bjorn Andersson <andersson@kernel.org>;
> Changhuang Liang <changhuang.liang@starfivetech.com>; Jack Zhu
> <jack.zhu@starfivetech.com>; Palmer Dabbelt <palmer@dabbelt.com>; Shawn
> Guo <shawnguo@kernel.org>; christian.koenig@amd.com
> Subject: [PATCH 9/9] drm/verisilicon: Add starfive hdmi driver
> 
> Add HDMI dirver for StarFive SoC JH7110.
> 
> Signed-off-by: Keith Zhao <keith.zhao@starfivetech.com>
> ---
>  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