6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dom Cobley popcornmix@gmail.com
[ Upstream commit 223ee2567a55e4f80315c768d2969e6a3b9fb23d ]
Trying to read /sys/kernel/debug/dri/1/hdmi1_regs when the hdmi is disconnected results in a fatal system hang.
This is due to the pm suspend code disabling the dvp clock. That is just a gate of the 108MHz clock in DVP_HT_RPI_MISC_CONFIG, which results in accesses hanging AXI bus.
Protect against this.
Fixes: 25eb441d55d4 ("drm/vc4: hdmi: Add all the vc5 HDMI registers into the debugfs dumps") Signed-off-by: Dom Cobley popcornmix@gmail.com Reviewed-by: Maxime Ripard mripard@kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20240621152055.4180873-17-dave... Signed-off-by: Dave Stevenson dave.stevenson@raspberrypi.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/vc4/vc4_hdmi.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index c6e986f71a26f..d4487f4cb3034 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -179,6 +179,8 @@ static int vc4_hdmi_debugfs_regs(struct seq_file *m, void *unused) if (!drm_dev_enter(drm, &idx)) return -ENODEV;
+ WARN_ON(pm_runtime_resume_and_get(&vc4_hdmi->pdev->dev)); + drm_print_regset32(&p, &vc4_hdmi->hdmi_regset); drm_print_regset32(&p, &vc4_hdmi->hd_regset); drm_print_regset32(&p, &vc4_hdmi->cec_regset); @@ -188,6 +190,8 @@ static int vc4_hdmi_debugfs_regs(struct seq_file *m, void *unused) drm_print_regset32(&p, &vc4_hdmi->ram_regset); drm_print_regset32(&p, &vc4_hdmi->rm_regset);
+ pm_runtime_put(&vc4_hdmi->pdev->dev); + drm_dev_exit(idx);
return 0;