[PATCH 08/43] drm/amd/display: FEC overhead should be checked once for mst slot nums

[Lin, Wayne]

[Public]

Hi,

Thanks for the report!
We're going to revert it and cc to stable.

Regards,
Wayne
> -----Original Message-----
> From: Jiri Slaby <jirislaby at kernel.org>
> Sent: Thursday, July 18, 2024 3:09 PM
> To: Li, Roman <Roman.Li at amd.com>; amd-gfx at lists.freedesktop.org
> Cc: Wheeler, Daniel <Daniel.Wheeler at amd.com>; Wentland, Harry
> <Harry.Wentland at amd.com>; Li, Sun peng (Leo) <Sunpeng.Li at amd.com>;
> Siqueira, Rodrigo <Rodrigo.Siqueira at amd.com>; Pillai, Aurabindo
> <Aurabindo.Pillai at amd.com>; Lin, Wayne <Wayne.Lin at amd.com>; Chiu,
> Solomon <Solomon.Chiu at amd.com>; Gutierrez, Agustin
> <Agustin.Gutierrez at amd.com>; Mahfooz, Hamza
> <Hamza.Mahfooz at amd.com>; Wu, Hersen <hersenxs.wu at amd.com>
> Subject: Re: [PATCH 08/43] drm/amd/display: FEC overhead should be
> checked once for mst slot nums
>
> On 28. 03. 24, 20:50, Roman.Li at amd.com wrote:
> > From: Hersen Wu <hersenxs.wu at amd.com>
> >
> > [Why] Mst slot nums equals to pbn / pbn_div.
> >
> > Today, pbn_div refers to dm_mst_get_pbn_divider ->
> > dc_link_bandwidth_kbps. In dp_link_bandwidth_kbps, which includes
> > effect of FEC overhead already. As result, we should not include
> > effect of FEC overhead again while calculating pbn by kpbs_to_peak_pbn
> > (stream_kbps).
> >
> > [How] Include FEC overhead within dp_link_bandwidth_kbps.
> > Remove FEC overhead from kbps_to_peak_pbn.
>
> Hi, this 6.10 commit (8b2cb32cf0c613) causes my secondary monitor not to
> come up at all.
>
> Reverting this on top of 6.10 makes it work again.
>
> Reported as (more details):
> https://gitlab.freedesktop.org/drm/amd/-/issues/3495
> https://bugzilla.suse.com/show_bug.cgi?id=1228093
>
> > Reviewed-by: Wayne Lin <wayne.lin at amd.com>
> > Acked-by: Roman Li <roman.li at amd.com>
> > Signed-off-by: Hersen Wu <hersenxs.wu at amd.com>
> > Tested-by: Daniel Wheeler <daniel.wheeler at amd.com>
> > ---
> >   .../display/amdgpu_dm/amdgpu_dm_mst_types.c   | 37 +++++--------------
> >   .../display/amdgpu_dm/amdgpu_dm_mst_types.h   |  3 --
> >   2 files changed, 10 insertions(+), 30 deletions(-)
>
> thanks,
> --
> js
> suse labs