[Intel-gfx] [PATCH resend 2/2] drm/i915/display: Make vlv_find_free_pps() skip pipes which are in use for non DP purposes
Hans de Goede
hdegoede at redhat.com
Tue Mar 23 10:39:09 UTC 2021
Hi,
On 3/2/21 3:51 PM, Ville Syrjälä wrote:
> On Tue, Mar 02, 2021 at 01:00:40PM +0100, Hans de Goede wrote:
>> As explained by a long comment block, on VLV intel_setup_outputs()
>> sometimes thinks there might be an eDP panel connected while there is none.
>> In this case intel_setup_outputs() will call intel_dp_init() to check.
>>
>> In this scenario vlv_find_free_pps() ends up selecting pipe A for the pps,
>> even though this might be in use for non DP purposes. When this is the case
>> then the assert_pipe() in vlv_force_pll_on() will fail when called from
>> vlv_power_sequencer_kick().
>
> The idea is that you *can* select a PPS from a pipe used for a non-DP
> port since those don't care about the PPS stuff. So this doesn't seem
> correct.
They may not care about the PPS stuff, but as the WARN / backtrace
shows if the DPLL_VCO_ENABLE bit is not already set for the pipe, while
the pipe is "otherwise" in use then vlv_force_pll_on() becomes unhappy
triggering the WARN.
> a) I would like to see the VBT for this machine
https://fedorapeople.org/~jwrdegoede/voyo-winpad-a15-vbt
> b) I wonder if the DSI PLL is sufficient for getting the PPS going?
I have no idea, I just noticed the WARN / backtrace and this seemed
like a reasonably way to deal with it. With that said I'm fine with fixing
this a different way.
> c) If we do need the normal DPLL is there any harm to DSI in enabling it?
I would assume this increases power-consumption and DSI panels are almost
always used in battery powered devices.
Also this would impact all BYT/CHT devices, possible triggering unwanted
side-effects. Where as the proposed fix below is much more narrowly targeted
at the problem. It might not be the most pretty fix but AFAICT it has a low
risk of causing regressions.
Regards,
Hans
>
>>
>> This happens on a Voyo winpad A15, leading to the following WARN/backtrace:
>>
>> [ 8.661531] ------------[ cut here ]------------
>> [ 8.661590] transcoder A assertion failure (expected off, current on)
>> [ 8.661647] WARNING: CPU: 2 PID: 243 at drivers/gpu/drm/i915/display/intel_display.c:1288 assert_pipe+0x125/0xc20 [i915]
>> [ 8.661822] Modules linked in: i915(E+) mmc_block crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel i2c_algo_bit drm_kms_helper cec drm drm_privacy_screen_helper video(E) sdhci_acpi sdhci i2c_hid pwm_lpss_platform pwm_lpss mmc_core i2c_dev fuse
>> [ 8.661944] CPU: 2 PID: 243 Comm: systemd-udevd Tainted: G E 5.11.0-rc5+ #228
>> [ 8.661954] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 11/20/2014
>> [ 8.661961] RIP: 0010:assert_pipe+0x125/0xc20 [i915]
>> [ 8.662050] Code: c7 c2 e5 39 4a c0 74 c9 48 c7 c6 53 3b 4a c0 83 fb 06 77 0a 89 db 48 8b 34 dd 80 38 45 c0 48 c7 c7 c8 ff 47 c0 e8 13 6c 8f df <0f> 0b e9 1d ff ff ff 89 db 48 8b 34 dd 80 38 45 c0 eb a0 48 c7 c2
>> [ 8.662058] RSP: 0018:ffffa939c0557690 EFLAGS: 00010286
>> [ 8.662071] RAX: 0000000000000039 RBX: 0000000000000000 RCX: ffff89c67bd19058
>> [ 8.662078] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff89c67bd19050
>> [ 8.662085] RBP: ffff89c64a3c0000 R08: 0000000000000001 R09: 0000000000000001
>> [ 8.662091] R10: ffffa939c05574c0 R11: ffffffffa0961248 R12: 0000000000000009
>> [ 8.662098] R13: 0000000000000000 R14: 00000000e0000000 R15: ffff89c64a3c0000
>> [ 8.662105] FS: 00007fe824e42380(0000) GS:ffff89c67bd00000(0000) knlGS:0000000000000000
>> [ 8.662113] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [ 8.662120] CR2: 00007fffdc770558 CR3: 0000000106ab8000 CR4: 00000000001006e0
>> [ 8.662127] Call Trace:
>> [ 8.662148] assert_pipe+0xa9e/0xc20 [i915]
>> [ 8.662252] vlv_force_pll_on+0xfb/0x1b0 [i915]
>> [ 8.662344] intel_dp_sync_state+0xd92/0x2e70 [i915]
>> [ 8.662448] intel_dp_sync_state+0x1908/0x2e70 [i915]
>> [ 8.662541] intel_dp_sync_state+0x1a3e/0x2e70 [i915]
>> [ 8.662620] ? recalibrate_cpu_khz+0x10/0x10
>> [ 8.662633] ? ktime_get_with_offset+0xad/0x160
>> [ 8.662658] intel_dp_sync_state+0x1f21/0x2e70 [i915]
>> [ 8.662788] intel_dp_encoder_suspend+0x41f/0x14b0 [i915]
>> [ 8.662875] ? drm_dp_dpcd_access+0x50/0xf0 [drm_kms_helper]
>> [ 8.662940] ? __mutex_lock+0x7e/0x7a0
>> [ 8.662950] ? drm_dp_dpcd_access+0x50/0xf0 [drm_kms_helper]
>> [ 8.662982] ? drm_dp_dpcd_access+0x50/0xf0 [drm_kms_helper]
>> [ 8.663025] intel_dp_encoder_suspend+0xdf3/0x14b0 [i915]
>> [ 8.663112] ? find_held_lock+0x2b/0x80
>> [ 8.663132] drm_dp_dpcd_access+0x62/0xf0 [drm_kms_helper]
>> [ 8.663181] drm_dp_dpcd_read+0xb6/0xf0 [drm_kms_helper]
>> [ 8.663223] drm_dp_read_dpcd_caps+0x20/0x110 [drm_kms_helper]
>> [ 8.663262] intel_dp_init_connector+0x79e/0x1010 [i915]
>> [ 8.663366] intel_dp_init+0x251/0x480 [i915]
>> [ 8.663453] intel_modeset_init_nogem+0x1998/0x1b70 [i915]
>> [ 8.663540] ? intel_pcode_init+0x3b6b/0x5d60 [i915]
>> [ 8.663625] i915_driver_probe+0x5d5/0xcb0 [i915]
>> [ 8.663734] ? drm_privacy_screen_get+0x163/0x1a0 [drm_privacy_screen_helper]
>> [ 8.663759] i915_params_free+0x11a/0x200 [i915]
>> [ 8.663830] ? __pm_runtime_resume+0x58/0x90
>> [ 8.663849] local_pci_probe+0x42/0x80
>> [ 8.663869] pci_device_probe+0xd9/0x190
>> [ 8.663892] really_probe+0xf2/0x440
>> [ 8.663915] driver_probe_device+0xe1/0x150
>> [ 8.663930] device_driver_attach+0xa8/0xb0
>> [ 8.663948] __driver_attach+0x8c/0x150
>> [ 8.663957] ? device_driver_attach+0xb0/0xb0
>> [ 8.663966] ? device_driver_attach+0xb0/0xb0
>> [ 8.663979] bus_for_each_dev+0x67/0x90
>> [ 8.663998] bus_add_driver+0x12e/0x1f0
>> [ 8.664015] driver_register+0x8b/0xe0
>> [ 8.664025] ? 0xffffffffc055a000
>> [ 8.664039] init_module+0x62/0x7c [i915]
>> [ 8.664127] do_one_initcall+0x5b/0x2d0
>> [ 8.664143] ? rcu_read_lock_sched_held+0x3f/0x80
>> [ 8.664155] ? kmem_cache_alloc_trace+0x292/0x2c0
>> [ 8.664178] do_init_module+0x5c/0x260
>> [ 8.664194] __do_sys_init_module+0x13d/0x1a0
>> [ 8.664247] do_syscall_64+0x33/0x40
>> [ 8.664260] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> [ 8.664272] RIP: 0033:0x7fe825d9a6be
>> [ 8.664284] Code: 48 8b 0d bd 27 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 af 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8a 27 0c 00 f7 d8 64 89 01 48
>> [ 8.664293] RSP: 002b:00007fffdc778028 EFLAGS: 00000246 ORIG_RAX: 00000000000000af
>> [ 8.664307] RAX: ffffffffffffffda RBX: 00005573f0770cf0 RCX: 00007fe825d9a6be
>> [ 8.664314] RDX: 00007fe825ed035a RSI: 000000000052b0a0 RDI: 00005573f112ae10
>> [ 8.664321] RBP: 00005573f112ae10 R08: 00005573f112ae10 R09: 00007fffdc774f70
>> [ 8.664328] R10: 00005573f0759010 R11: 0000000000000246 R12: 00007fe825ed035a
>> [ 8.664334] R13: 00005573f077e1e0 R14: 0000000000000007 R15: 00005573f077f2d0
>> [ 8.664379] irq event stamp: 126913
>> [ 8.664385] hardirqs last enabled at (126919): [<ffffffff9f162af9>] console_unlock+0x4e9/0x600
>> [ 8.664397] hardirqs last disabled at (126924): [<ffffffff9f162a6c>] console_unlock+0x45c/0x600
>> [ 8.664406] softirqs last enabled at (126624): [<ffffffff9fe01112>] asm_call_irq_on_stack+0x12/0x20
>> [ 8.664416] softirqs last disabled at (126619): [<ffffffff9fe01112>] asm_call_irq_on_stack+0x12/0x20
>> [ 8.664426] ---[ end trace 5049606d4dbfaebc ]---
>>
>> Add a check for the combination of the DPLL not being enabled (indicating
>> that DP is not active on the pipe), while the pipe is enabled; and when
>> both conditions are true don't use the pipe for pps. This fixes the above
>> WARN/backtrace. After this the attempt to detect the non existing eDP
>> panel on port B results in the following 2 info messages:
>>
>> [ 8.461967] i915 0000:00:02.0: [drm] Pipe A is used for non DP, not using it for pps
>> [ 8.675304] i915 0000:00:02.0: [drm] failed to retrieve link info, disabling eDP
>>
>> Indicating that everything is working as it should.
>>
>> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
>> ---
>> drivers/gpu/drm/i915/display/intel_pps.c | 22 ++++++++++++++++++++++
>> 1 file changed, 22 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_pps.c b/drivers/gpu/drm/i915/display/intel_pps.c
>> index f20ba71f4307..757e82825919 100644
>> --- a/drivers/gpu/drm/i915/display/intel_pps.c
>> +++ b/drivers/gpu/drm/i915/display/intel_pps.c
>> @@ -121,6 +121,7 @@ static enum pipe vlv_find_free_pps(struct drm_i915_private *dev_priv)
>> {
>> struct intel_encoder *encoder;
>> unsigned int pipes = (1 << PIPE_A) | (1 << PIPE_B);
>> + enum pipe pipe;
>>
>> /*
>> * We don't have power sequencer currently.
>> @@ -146,6 +147,27 @@ static enum pipe vlv_find_free_pps(struct drm_i915_private *dev_priv)
>> }
>> }
>>
>> + /*
>> + * If the DPLL is not enabled and the pipe is enabled then the pipe is
>> + * in use for non DP uses. In this case we *must* not use it for pps.
>> + * This may happen when PIPE A is used for a DSI panel, yet the VLV code
>> + * in intel_setup_outputs() thinks port B may be used for eDP and calls
>> + * intel_dp_init() to check.
>> + */
>> + for (pipe = PIPE_A; pipe <= PIPE_B; pipe++) {
>> + if (!(pipes & (1 << pipe)))
>> + continue;
>> +
>> + if (intel_de_read(dev_priv, DPLL(pipe)) & DPLL_VCO_ENABLE)
>> + continue;
>> +
>> + if (intel_pipe_is_enabled(dev_priv, (enum transcoder)pipe)) {
>> + drm_info(&dev_priv->drm, "Pipe %c is used for non DP, not using it for pps\n",
>> + pipe_name(pipe));
>> + pipes &= ~(1 << pipe);
>> + }
>> + }
>> +
>> if (pipes == 0)
>> return INVALID_PIPE;
>>
>> --
>> 2.30.1
>
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