Re: [PATCH] Revert "drm/display/dp_mst: Move all payload info into the atomic state"

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Jan 27, 2023 at 03:02:41PM +0000, Limonciello, Mario wrote:
> [Public]
> 
> 
> 
> > -----Original Message-----
> > From: Linux kernel regression tracking (Thorsten Leemhuis)
> > <regressions@leemhuis.info>
> > Sent: Friday, January 27, 2023 03:15
> > To: Greg KH <gregkh@linuxfoundation.org>; Limonciello, Mario
> > <Mario.Limonciello@amd.com>
> > Cc: dri-devel@lists.freedesktop.org; stable@vger.kernel.org;
> > stanislav.lisovskiy@intel.com; Zuo, Jerry <Jerry.Zuo@amd.com>; amd-
> > gfx@lists.freedesktop.org; Lin, Wayne <Wayne.Lin@amd.com>; Guenter
> > Roeck <linux@roeck-us.net>; bskeggs@redhat.com
> > Subject: Re: [PATCH] Revert "drm/display/dp_mst: Move all payload info into
> > the atomic state"
> > 
> > On 27.01.23 08:39, Greg KH wrote:
> > > On Fri, Jan 20, 2023 at 11:51:04AM -0600, Limonciello, Mario wrote:
> > >> On 1/20/2023 11:46, Guenter Roeck wrote:
> > >>> On Thu, Jan 12, 2023 at 04:50:44PM +0800, Wayne Lin wrote:
> > >>>> This reverts commit 4d07b0bc403403438d9cf88450506240c5faf92f.
> > >>>>
> > >>>> [Why]
> > >>>> Changes cause regression on amdgpu mst.
> > >>>> E.g.
> > >>>> In fill_dc_mst_payload_table_from_drm(), amdgpu expects to
> > add/remove payload
> > >>>> one by one and call fill_dc_mst_payload_table_from_drm() to update
> > the HW
> > >>>> maintained payload table. But previous change tries to go through all
> > the
> > >>>> payloads in mst_state and update amdpug hw maintained table in once
> > everytime
> > >>>> driver only tries to add/remove a specific payload stream only. The
> > newly
> > >>>> design idea conflicts with the implementation in amdgpu nowadays.
> > >>>>
> > >>>> [How]
> > >>>> Revert this patch first. After addressing all regression problems caused
> > by
> > >>>> this previous patch, will add it back and adjust it.
> > >>>
> > >>> Has there been any progress on this revert, or on fixing the underlying
> > >>> problem ?
> > >>>
> > >>> Thanks,
> > >>> Guenter
> > >>
> > >> Hi Guenter,
> > >>
> > >> Wayne is OOO for CNY, but let me update you.
> > >>
> > >> Harry has sent out this series which is a collection of proper fixes.
> > >> https://patchwork.freedesktop.org/series/113125/
> > >>
> > >> Once that's reviewed and accepted, 4 of them are applicable for 6.1.
> > >
> > > Any hint on when those will be reviewed and accepted?  patchwork
> > doesn't
> > > show any activity on them, or at least I can't figure it out...
> > 
> > I didn't look closer (hence please correct me if I'm wrong), but the
> > core changes afaics are in the DRM pull airlied send a few hours ago to
> > Linus (note the "amdgpu […] DP MST fixes" line):
> > 
> > https://lore.kernel.org/all/CAPM%3D9tzuu4xnx6T5v7sKsK%2BA5HEaPOc1ie
> > MyzNSYQZGztJ%3D6Qw@mail.gmail.com/
> 
> That's right.  There are 4 commits in that PR with the appropriate stable tags
> that should fix the majority of the MST issues introduced in 6.1 by 4d07b0bc40340
> ("drm/display/dp_mst: Move all payload info into the atomic state"):
> 
>       drm/amdgpu/display/mst: Fix mst_state->pbn_div and slot count assignments
>       drm/amdgpu/display/mst: limit payload to be updated one by one
>       drm/amdgpu/display/mst: update mst_mgr relevant variable when long HPD
>       drm/display/dp_mst: Correct the kref of port.
> 
> There will be follow ups for any remaining corner cases.

Great, thanks for this, all are now queued up in the 6.1.y queue.

greg k-h