Re: [PATCH v2 01/40] drm/i915/tgl: disable DDIC

Matt Roper
2019-08-19T17:17:00Z

On Sat, Aug 17, 2019 at 02:38:23AM -0700, Lucas De Marchi wrote:
> The current SKUs added for Tiger Lake don't have DDIC hooked up, even
> though it is supported by the SoC. The current state for these SKUs is
> problematic since while enabling the combo phy, PORT_COMP_DW* return
> 0xFFFFFFFF, which is invalid per register definition.

If this is always the case on these platforms, can we test for this
specific invalid value at the beginning of icl_combo_phys_init() and set
a quirk flag that can be used later to decide whether to disable DDI-C?

Matt

>
> During initialization we check what phys are not yet enabled by reading
> PHY_MISC_C and try to enable it by toggling the "DE to IO Comp Pwr Down"
> bit. But after that any read to the PORT_COMP_DW* returns invalid
> results. This removes the following warning
>
> [56997.634353] Missing case (val == 4294967295)
> [56997.639241] WARNING: CPU: 5 PID: 768 at drivers/gpu/drm/i915/display/intel_combo_phy.c:54 cnl_get_procmon_ref_values+0xc9/0xf0 [i915]
> [56997.639808] Modules linked in: i915(+) prime_numbers x86_pkg_temp_thermal coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel e1000e [last unloaded: prime_numbers]
> [56997.639808] CPU: 5 PID: 768 Comm: insmod Tainted: G U W 5.2.0-demarchi+ #65
> [56997.639808] Hardware name: Intel Corporation Tiger Lake Client Platform/TigerLake U DDR4 SODIMM RVP, BIOS TGLSFWI1.R00.2252.A03.1906270154 06/27/2019
> [56997.639808] RIP: 0010:cnl_get_procmon_ref_values+0xc9/0xf0 [i915]
> [56997.639808] Code: 2c a0 85 c9 74 e0 81 f9 00 00 00 01 75 09 48 c7 c0 0c a4 2c a0 eb cf 48 c7 c6 3c 3a 31 a0 48 c7 c7 40 3a 31 a0 e8 6b 4d ea e0 <0f> 0b 48 c7 c0 00 a4 2c a0 eb b1 48 c7 c0 24 a4 2
> c a0 eb a8 e8 be
> [56997.639808] RSP: 0018:ffffc9000068f8a8 EFLAGS: 00010286
> [56997.639808] RAX: 0000000000000000 RBX: ffff88848fa90000 RCX: 0000000000000000
> [56997.639808] RDX: ffff8884a08b5ef8 RSI: ffff8884a08a6658 RDI: 00000000ffffffff
> [56997.639808] RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
> [56997.639808] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88848fa90000
> [56997.639808] R13: 0000000000000000 R14: 0000000000000002 R15: 0006c00000162000
> [56997.639808] FS: 00007f61ca3d12c0(0000) GS:ffff8884a0880000(0000) knlGS:0000000000000000
> [56997.639808] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [56997.639808] CR2: 00007f71be6a92c0 CR3: 0000000494750006 CR4: 0000000000760ee0
> [56997.639808] PKRU: 55555554
> [56997.639808] Call Trace:
> [56997.639808] cnl_verify_procmon_ref_values+0x36/0xf0 [i915]
> [56997.639808] ? rcu_read_lock_sched_held+0x6f/0x80
> [56997.639808] ? gen11_fwtable_read32+0x257/0x290 [i915]
> [56997.639808] icl_combo_phy_verify_state.part.0+0x22/0xa0 [i915]
> [56997.639808] intel_combo_phy_init+0x17e/0x3e0 [i915]
> [56997.639808] ? icl_display_core_init+0x2c/0x1a0 [i915]
> [56997.639808] ? _raw_spin_unlock_irqrestore+0x4c/0x60
> [56997.639808] icl_display_core_init+0x34/0x1a0 [i915]
> [56997.639808] intel_power_domains_init_hw+0x200/0x570 [i915]
> [56997.639808] i915_driver_probe+0x103b/0x17e0 [i915]
> [56997.639808] ? printk+0x53/0x6a
> [56997.639808] i915_pci_probe+0x3b/0x190 [i915]
>
> We may or may not need to change the implementation to account for DDIC
> being available on other SKUs. For now I think the best thing to do is
> to just disable the port.
>
> v2: Fix checkpatch warning on commit message
>
> Cc: José Roberto de Souza <jose.souza@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_display.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index ee54d9659c99..b51d1ceb8739 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -6667,7 +6667,7 @@ bool intel_phy_is_combo(struct drm_i915_private *dev_priv, enum phy phy)
> if (phy == PHY_NONE)
> return false;
>
> - if (IS_ELKHARTLAKE(dev_priv) || INTEL_GEN(dev_priv) >= 12)
> + if (IS_ELKHARTLAKE(dev_priv))
> return phy <= PHY_C;
>
> if (INTEL_GEN(dev_priv) >= 11)
> @@ -15299,7 +15299,6 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv)
> /* TODO: initialize TC ports as well */
> intel_ddi_init(dev_priv, PORT_A);
> intel_ddi_init(dev_priv, PORT_B);
> - intel_ddi_init(dev_priv, PORT_C);
> icl_dsi_init(dev_priv);
> } else if (IS_ELKHARTLAKE(dev_priv)) {
> intel_ddi_init(dev_priv, PORT_A);
> --
> 2.21.0
>
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> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
(916) 356-2795