On 10.09.20 20:18, Deucher, Alexander wrote:
> [AMD Public Use]
>
>
>
>> -----Original Message-----
>> From: amd-gfx <amd-gfx-boun...@lists.freedesktop.org> On Behalf Of
>> Daniel Vetter
>> Sent: Monday, September 7, 2020 3:15 AM
>> To: Jan Kiszka <jan.kis...@web.de>; amd-gfx list <amd-
>> g...@lists.freedesktop.org>; Wentland, Harry <harry.wentl...@amd.com>;
>> Kazlauskas, Nicholas <nicholas.kazlaus...@amd.com>
>> Cc: dri-devel <dri-de...@lists.freedesktop.org>; intel-gfx <intel-
>> g...@lists.freedesktop.org>; Thomas Zimmermann
>> <tzimmerm...@suse.de>; Ville Syrjala <ville.syrj...@linux.intel.com>
>> Subject: Re: [PATCH v3 6/7] drm: Validate encoder->possible_crtcs
>>
>> On Sun, Sep 6, 2020 at 1:19 PM Jan Kiszka <jan.kis...@web.de> wrote:
>>>
>>> On 11.02.20 18:04, Daniel Vetter wrote:
>>>> On Tue, Feb 11, 2020 at 06:22:07PM +0200, Ville Syrjala wrote:
>>>>> From: Ville Syrjälä <ville.syrj...@linux.intel.com>
>>>>>
>>>>> WARN if the encoder possible_crtcs is effectively empty or contains
>>>>> bits for non-existing crtcs.
>>>>>
>>>>> v2: Move to drm_mode_config_validate() (Daniel)
>>>>> Make the docs say we WARN when this is wrong (Daniel)
>>>>> Extract full_crtc_mask()
>>>>>
>>>>> Cc: Thomas Zimmermann <tzimmerm...@suse.de>
>>>>> Cc: Daniel Vetter <dan...@ffwll.ch>
>>>>> Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
>>>>
>>>> When pushing the fixup needs to be applied before the validation
>>>> patch here, because we don't want to anger the bisect gods.
>>>>
>>>> Reviewed-by: Daniel Vetter <daniel.vet...@ffwll.ch>
>>>>
>>>> I think with the fixup we should be good enough with the existing
>>>> nonsense in drivers. Fingers crossed.
>>>> -Daniel
>>>>
>>>>
>>>>> ---
>>>>> drivers/gpu/drm/drm_mode_config.c | 27
>> ++++++++++++++++++++++++++-
>>>>> include/drm/drm_encoder.h | 2 +-
>>>>> 2 files changed, 27 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/drm_mode_config.c
>>>>> b/drivers/gpu/drm/drm_mode_config.c
>>>>> index afc91447293a..4c1b350ddb95 100644
>>>>> --- a/drivers/gpu/drm/drm_mode_config.c
>>>>> +++ b/drivers/gpu/drm/drm_mode_config.c
>>>>> @@ -581,6 +581,29 @@ static void
>> validate_encoder_possible_clones(struct drm_encoder *encoder)
>>>>> encoder->possible_clones, encoder_mask); }
>>>>>
>>>>> +static u32 full_crtc_mask(struct drm_device *dev) {
>>>>> + struct drm_crtc *crtc;
>>>>> + u32 crtc_mask = 0;
>>>>> +
>>>>> + drm_for_each_crtc(crtc, dev)
>>>>> + crtc_mask |= drm_crtc_mask(crtc);
>>>>> +
>>>>> + return crtc_mask;
>>>>> +}
>>>>> +
>>>>> +static void validate_encoder_possible_crtcs(struct drm_encoder
>>>>> +*encoder) {
>>>>> + u32 crtc_mask = full_crtc_mask(encoder->dev);
>>>>> +
>>>>> + WARN((encoder->possible_crtcs & crtc_mask) == 0 ||
>>>>> + (encoder->possible_crtcs & ~crtc_mask) != 0,
>>>>> + "Bogus possible_crtcs: "
>>>>> + "[ENCODER:%d:%s] possible_crtcs=0x%x (full crtc mask=0x%x)\n",
>>>>> + encoder->base.id, encoder->name,
>>>>> + encoder->possible_crtcs, crtc_mask); }
>>>>> +
>>>>> void drm_mode_config_validate(struct drm_device *dev) {
>>>>> struct drm_encoder *encoder;
>>>>> @@ -588,6 +611,8 @@ void drm_mode_config_validate(struct
>> drm_device *dev)
>>>>> drm_for_each_encoder(encoder, dev)
>>>>> fixup_encoder_possible_clones(encoder);
>>>>>
>>>>> - drm_for_each_encoder(encoder, dev)
>>>>> + drm_for_each_encoder(encoder, dev) {
>>>>> validate_encoder_possible_clones(encoder);
>>>>> + validate_encoder_possible_crtcs(encoder);
>>>>> + }
>>>>> }
>>>>> diff --git a/include/drm/drm_encoder.h b/include/drm/drm_encoder.h
>>>>> index 3741963b9587..b236269f41ac 100644
>>>>> --- a/include/drm/drm_encoder.h
>>>>> +++ b/include/drm/drm_encoder.h
>>>>> @@ -142,7 +142,7 @@ struct drm_encoder {
>>>>> * the bits for all &drm_crtc objects this encoder can be connected
>>>>> to
>>>>> * before calling drm_dev_register().
>>>>> *
>>>>> - * In reality almost every driver gets this wrong.
>>>>> + * You will get a WARN if you get this wrong in the driver.
>>>>> *
>>>>> * Note that since CRTC objects can't be hotplugged the assigned
>> indices
>>>>> * are stable and hence known before registering all objects.
>>>>> --
>>>>> 2.24.1
>>>>>
>>>>
>>>
>>> Triggers on an Advantech AIMB-228 (R1505G, 3 DP outputs):
>>
>> Adding amdgpu display folks.
>
> I took a quick look at this and it looks like we limit the number of crtcs
> later in the mode init process if the number of physical displays can't
> actually use more crtcs. E.g., the physical board configuration would only
> allow for 3 active displays even if the hardware technically supports 4
> crtcs. I presume that way we can just leave the additional hardware power
> gated all the time.
>
So, will this be fixed any time soon? I don't feel qualified writing
such a patch but I would obviously be happy to test one.
Jan
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