diff options
| author | Maxime Ripard <maxime@cerno.tech> | 2021-09-22 14:54:17 +0200 |
|---|---|---|
| committer | Maxime Ripard <maxime@cerno.tech> | 2021-10-25 15:33:40 +0200 |
| commit | 3e85b81591609bb794bb00cd619b20965b5b38cd (patch) | |
| tree | 1d99096a575969e2302f1c93c0891e98333db1ec /drivers/gpu/drm/vc4/vc4_hdmi.c | |
| parent | 8ca011ef4af48a7af7b15afd8a4a44039dd04cea (diff) | |
| download | linux-3e85b81591609bb794bb00cd619b20965b5b38cd.tar.bz2 | |
drm/vc4: hdmi: Set a default HSM rate
When the firmware doesn't setup the HSM rate (such as when booting
without an HDMI cable plugged in), its rate is 0 and thus any register
access results in a CPU stall, even though HSM is enabled.
Let's enforce a minimum rate at boot to avoid this issue.
Fixes: 4f6e3d66ac52 ("drm/vc4: Add runtime PM support to the HDMI encoder driver")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Tested-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Tested-by: Michael Stapelberg <michael@stapelberg.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922125419.4125779-4-maxime@cerno.tech
Diffstat (limited to 'drivers/gpu/drm/vc4/vc4_hdmi.c')
| -rw-r--r-- | drivers/gpu/drm/vc4/vc4_hdmi.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index 1bc675d727b6..a3813a6137fb 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -94,6 +94,7 @@ # define VC4_HD_M_SW_RST BIT(2) # define VC4_HD_M_ENABLE BIT(0) +#define HSM_MIN_CLOCK_FREQ 120000000 #define CEC_CLOCK_FREQ 40000 #define HDMI_14_MAX_TMDS_CLK (340 * 1000 * 1000) @@ -2170,6 +2171,19 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data) vc4_hdmi->disable_4kp60 = true; } + /* + * If we boot without any cable connected to the HDMI connector, + * the firmware will skip the HSM initialization and leave it + * with a rate of 0, resulting in a bus lockup when we're + * accessing the registers even if it's enabled. + * + * Let's put a sensible default at runtime_resume so that we + * don't end up in this situation. + */ + ret = clk_set_min_rate(vc4_hdmi->hsm_clock, HSM_MIN_CLOCK_FREQ); + if (ret) + goto err_put_ddc; + if (vc4_hdmi->variant->reset) vc4_hdmi->variant->reset(vc4_hdmi); |