Re: [PATCH] drm/i915/hdcp: Make hdcp2_encrypted and hdcp_encrypted mutually exclusive

On 17-07-2026 09:17, Suraj Kandpal wrote:
> With introduction of force_hdcp14 we can now for HDCP 1.4 by passing
> HDCP 2.2 authentication but In MST, _intel_hdcp_disable() and
> _intel_hdcp2_disable() can return early
> when there are still other streams active on the port (num_streams > 0),
> leaving the per-connector hdcp_encrypted / hdcp2_encrypted flag stale.
> If the same connector is later re-enabled with the other HDCP version
> (e.g. HDCP 1.4 via force_hdcp14 after a prior HDCP 2.2 session on that
> connector) the stale flag from the previous protocol survives.
> intel_hdcp_disable() then picks the wrong branch on the next disable
> causing the following splat.
> 
> xe 0000:00:02.0: [drm]
> drm_WARN_ON(!(intel_de_read(display,
> ((((&(display)->info.__runtime_info)->ip.ver) >= 12) ? ((const
> i915_reg_t){ .reg = (((0x664B4) + (cpu_transcoder) * ((0x665B4) -
> (0x664B4)))) }) : ((const i915_reg_t){ .reg = ((((const u32 []){
> 0x66800, 0x66500, 0x66600, 0x66700, 0x66A00, 0x66900 })[(port)]) +
> (0xB4)) }))) & ((u32)(((int)sizeof(struct
> {_Static_assert(!(__builtin_choose_expr((sizeof(int) == sizeof(*(8 ?
> ((void *)((long)((20) >= (sizeof(u32) * 8)) * 0l)) : (int *)8))), (20)
>> = (sizeof(u32) * 8), false)), "const_true((20) >= BITS_PER_TYPE(u32))"
> " is true");})) + ((((1ULL))) << (20))))))
> WARNING:
> drivers/gpu/drm/i915/display/intel_hdcp.c:1969 at
> _intel_hdcp2_disable+0x4bf/0x520 [xe], CPU#2: kms_content_pro/101318
> Modules linked in: xe vfio_pci_core vfio_iommu_type1
> vfio iommufd xt_multiport snd_hda_codec_intelhdmi snd_hda_codec_hdmi
> drm_gpuvm drm_gpusvm_helper drm_buddy gpu_sched drm_ttm_helper ttm
> drm_suballoc_helper drm_exec drm_display_helper cec rc_core
> drm_kunit_helpers kunit i2c_algo_bit xt_conntrack xt_MASQUERADE bridge
> stp llc nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
> xt_addrtype nft_compat x_tables nf_tables xfrm_user xfrm_algo overlay
> cpuid cmdlinepart spi_nor mei_gsc_proxy mtd intel_rapl_msr wmi_bmof
> intel_uncore_frequency intel_uncore_frequency_common
> x86_pkg_temp_thermal intel_powerclamp coretemp snd_intel_dspcfg
> aesni_intel snd_hda_codec gf128mul snd_hda_core snd_hwdep r8169 snd_pcm
> intel_cstate snd_timer i2c_i801 i2c_mux snd spi_intel_pci
> processor_thermal_device_pci realtek video e1000e spi_intel i2c_smbus
> soundcore phy_package processor_thermal_device processor_thermal_wt_hint
> mei_me platform_temperature_control processor_thermal_soc_slider idma64
> mei processor_thermal_rfim
> processor_thermal_rapl intel_ish_ipc
> intel_rapl_common intel_ishtp thunderbolt processor_thermal_wt_req
> processor_thermal_power_floor intel_vpu processor_thermal_mbox
> igen6_edac wmi sunrpc kvm_intel binfmt_misc kvm irqbypass
> int3403_thermal int340x_thermal_zone intel_skl_int3472_tps68470
> tps68470_regulator intel_pmc_core clk_tps68470 acpi_tad int3400_thermal
> intel_hid pmt_telemetry acpi_thermal_rel sparse_keymap pmt_discovery
> pinctrl_intel_platform pmt_class intel_pmc_ssram_telemetry
> intel_pmc_pwrm_telemetry intel_skl_int3472_discrete
> intel_skl_int3472_common acpi_pad intel_vsec nls_iso8859_1 dm_multipath
> msr fuse efi_pstore autofs4 [last unloaded: xe_live_test]
> CPU: 2 UID: 0 PID: 101318 Comm: kms_content_pro Kdump:
> loaded Tainted: G     U       L   N
> 7.2.0-rc2-lgci-xe-xe-5389-67aa8ad5c4c59cd1a-debug+ #1 PREEMPT(lazy)
> Tainted: [U]=USER, [L]=SOFTLOCKUP, [N]=TEST
> Hardware name: Intel Corporation Panther Lake Client
> Platform/PTL-UH LP5 T3 RVP1, BIOS PTLPFWI1.R00.3514.D01.2512291130
> 12/29/2025
> RIP: 0010:_intel_hdcp2_disable+0x4c9/0x520 [xe]
> Code: 85 ff 74 04 48 8b 7f 08 4c 8b 7f 50 4d 85 ff 74
> 23 e8 5b 80 df e0 48 89 c6 48 8d 3d b1 f7 ba ff 48 c7 c1 a0 27 6a a1 4c
>     89 fa <67> 48 0f b9 3a e9 c9 fc ff ff 4c 8b 3f eb d8 e8 33 45 4e e1
>        4c 89
> RSP: 0018:ffffc900027bf738 EFLAGS: 00010246
> RAX: ffffffffa16bd4f1 RBX: ffff8881a1e69000 RCX:
> ffffffffa16a27a0
> RDX: ffff8881c7b1b190 RSI: ffffffffa16bd4f1 RDI:
> ffffffffa100de30
> RBP: ffffc900027bf7b0 R08: 0000000000000000 R09:
> 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12:
> ffff88844397a000
> R13: ffff88844397a000 R14: ffff88817f7d2000 R15:
> ffff8881c7b1b190
> FS:  0000774e9299dbc0(0000) GS:ffff8884eb36c000(0000)
> knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000774e94bc7220 CR3: 00000002166c1002 CR4:
> 0000000108f72ef0
> PKRU: 55555554
> Call Trace:
>   <TASK>
>   ? intel_hdcp_update_value+0x7d/0x260 [xe]
>   intel_hdcp_disable+0x118/0x130 [xe]
>   intel_hdcp_update_pipe+0x175/0x1b0 [xe]
>   ? intel_initial_watermarks+0x20/0x60 [xe]
>   intel_ddi_update_pipe+0x44/0xb0 [xe]
>   intel_pre_update_crtc+0x3bc/0x410 [xe]
>   skl_commit_modeset_enables+0x1a7/0x890 [xe]
>   ? icl_sagv_pre_plane_update+0x6c/0xf0 [xe]
>   intel_atomic_commit_tail+0x114b/0x20a0 [xe]
>   ? lock_release+0xd0/0x2a0
>   intel_atomic_commit+0x2ff/0x350 [xe]
>   ? intel_atomic_commit+0x2ff/0x350 [xe]
>   drm_atomic_commit+0xaf/0xf0
>   ? __pfx___drm_printfn_info+0x10/0x10
>   drm_mode_atomic_ioctl+0xcb5/0xf60
>   ? drm_mode_atomic_ioctl+0x8a8/0xf60
>   ? drm_mode_atomic_ioctl+0x604/0xf60
>   ? __pfx_drm_mode_atomic_ioctl+0x10/0x10
>   drm_ioctl_kernel+0xb3/0x120
>   drm_ioctl+0x2db/0x5a0
>   ? __pfx_drm_mode_atomic_ioctl+0x10/0x10
>   ? _raw_spin_unlock_irqrestore+0x51/0x80
>   ? __pm_runtime_resume+0x5b/0x90
>   ? xe_pm_runtime_get_ioctl+0x61/0x150 [xe]
>   xe_drm_ioctl+0x64/0xb0 [xe]
>   __x64_sys_ioctl+0xa5/0x100
>   x64_sys_call+0x1250/0x26e0
>   do_syscall_64+0x103/0x6d0
>   ? __task_pid_nr_ns+0xc0/0x290
>   ? trace_hardirqs_on_prepare+0xcb/0xf0
>   ? do_syscall_64+0x34/0x6d0
>   ? fred_entry_from_user+0x92/0x140
>   ? trace_hardirqs_on+0x22/0xe0
>   ? do_syscall_64+0xb8/0x6d0
>   fred_entry_from_user+0x92/0x140
>   asm_fred_entrypoint_user+0x41/
> 
> Ensure the two flags are mutually exclusive at every successful enable:
> after intel_hdcp_auth() succeeds.
> 
> Signed-off-by: Suraj Kandpal <[email protected]>
Tested-by: Santhosh Reddy Guddati <[email protected]>
Reviewed-by: Santhosh Reddy Guddati <[email protected]>

> ---
>   drivers/gpu/drm/i915/display/intel_hdcp.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index 0a076d2ed70a..e56df337dc6d 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -1075,6 +1075,7 @@ static int intel_hdcp1_enable(struct intel_connector *connector)
>   		ret = intel_hdcp_auth(connector);
>   		if (!ret) {
>   			hdcp->hdcp_encrypted = true;
> +			hdcp->hdcp2_encrypted = false;
>   			return 0;
>   		}
>   
> @@ -2109,6 +2110,7 @@ static int _intel_hdcp2_enable(struct intel_atomic_state *state,
>   		    hdcp->content_type);
>   
>   	hdcp->hdcp2_encrypted = true;
> +	hdcp->hdcp_encrypted = false;
>   	return 0;
>   }
>