[PATCH] drm/amd/display: check plane state before validating fbc

Andrey Grodzovsky Andrey.Grodzovsky at amd.com
Mon Nov 27 12:38:21 UTC 2017



On 11/26/2017 11:57 AM, Harry Wentland wrote:
> On 2017-11-24 05:07 PM, Andrey Grodzovsky wrote:
>> The patch is good, but why validate_fbc is being called from dce110_apply_ctx_to_hw (atomic_commit) ? It should be called from atomic_check.
>>
> Ideally yes, but I don't think this has any impact on bandwidth and mode validation, i.e. we should never fail to apply an atomic state, no matter whether we do FBC. If we let user-mode decide whether to do FBC or not it would need to be a property and check in atomic_check but I don't think it makes any sense to expose this outside DC.
>
> Harry

I see, as long as enable_fbc return code is ignored as it is today that ok.

Thanks,
Andrey

>
>> Thanks,
>> Andrey
>>
>> On 2017-11-22 02:13 AM, S, Shirish wrote:
>>> From: Shirish S <shirish.s at amd.com>
>>>
>>> While validation fbc, array_mode of the pipe is accessed without checking plane_state exists for it.
>>> Causing to null pointer dereferencing followed by reboot when a crtc associated with external display(not
>>> connected) is page flipped.
>>>
>>> This patch adds a check for plane_state before using it to validate fbc.
>>>
>>> Signed-off-by: Shirish S <shirish.s at amd.com>
>>> Reviewed-by: Roman Li <Roman.Li at amd.com>
>>> ---
>>>    drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c | 4 ++++
>>>    1 file changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
>>> index ee3b944..a6cd63a 100644
>>> --- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
>>> +++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
>>> @@ -1724,6 +1724,10 @@ static enum dc_status validate_fbc(struct dc *dc,
>>>        if (pipe_ctx->stream->sink->link->psr_enabled)
>>>            return DC_ERROR_UNEXPECTED;
>>>    +    /* Nothing to compress */
>>> +    if (!pipe_ctx->plane_state)
>>> +        return DC_ERROR_UNEXPECTED;
>>> +
>>>        /* Only for non-linear tiling */
>>>        if (pipe_ctx->plane_state->tiling_info.gfx8.array_mode == DC_ARRAY_LINEAR_GENERAL)
>>>            return DC_ERROR_UNEXPECTED;
>>> -- 
>>> 2.7.4
>>>
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>>> amd-gfx at lists.freedesktop.org
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