* [PATCH] drm/tegra: dc: Restore coupling of display controllers
@ 2021-03-19 7:06 Thierry Reding
2021-03-19 12:06 ` Dmitry Osipenko
0 siblings, 1 reply; 2+ messages in thread
From: Thierry Reding @ 2021-03-19 7:06 UTC (permalink / raw)
To: Thierry Reding; +Cc: linux-tegra, Dmitry Osipenko, dri-devel
From: Thierry Reding <treding@nvidia.com>
Coupling of display controllers used to rely on runtime PM to take the
companion controller out of reset. Commit fd67e9c6ed5a ("drm/tegra: Do
not implement runtime PM") accidentally broke this when runtime PM was
removed.
Restore this functionality by reusing the hierarchical host1x client
suspend/resume infrastructure that's similar to runtime PM and which
perfectly fits this use-case.
Fixes: fd67e9c6ed5a ("drm/tegra: Do not implement runtime PM")
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
drivers/gpu/drm/tegra/dc.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 795b4e457ab6..2585ba70b706 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -2519,22 +2519,18 @@ static int tegra_dc_couple(struct tegra_dc *dc)
* POWER_CONTROL registers during CRTC enabling.
*/
if (dc->soc->coupled_pm && dc->pipe == 1) {
- u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_CONSUMER;
- struct device_link *link;
- struct device *partner;
+ struct device *companion;
+ struct tegra_dc *parent;
- partner = driver_find_device(dc->dev->driver, NULL, NULL,
- tegra_dc_match_by_pipe);
- if (!partner)
+ companion = driver_find_device(dc->dev->driver, NULL, (const void *)0,
+ tegra_dc_match_by_pipe);
+ if (!companion)
return -EPROBE_DEFER;
- link = device_link_add(dc->dev, partner, flags);
- if (!link) {
- dev_err(dc->dev, "failed to link controllers\n");
- return -EINVAL;
- }
+ parent = dev_get_drvdata(companion);
+ dc->client.parent = &parent->client;
- dev_dbg(dc->dev, "coupled to %s\n", dev_name(partner));
+ dev_dbg(dc->dev, "coupled to %s\n", dev_name(companion));
}
return 0;
--
2.30.2
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] drm/tegra: dc: Restore coupling of display controllers
2021-03-19 7:06 [PATCH] drm/tegra: dc: Restore coupling of display controllers Thierry Reding
@ 2021-03-19 12:06 ` Dmitry Osipenko
0 siblings, 0 replies; 2+ messages in thread
From: Dmitry Osipenko @ 2021-03-19 12:06 UTC (permalink / raw)
To: Thierry Reding, Paul Fertser; +Cc: linux-tegra, dri-devel
19.03.2021 10:06, Thierry Reding пишет:
> From: Thierry Reding <treding@nvidia.com>
>
> Coupling of display controllers used to rely on runtime PM to take the
> companion controller out of reset. Commit fd67e9c6ed5a ("drm/tegra: Do
> not implement runtime PM") accidentally broke this when runtime PM was
> removed.
>
> Restore this functionality by reusing the hierarchical host1x client
> suspend/resume infrastructure that's similar to runtime PM and which
> perfectly fits this use-case.
>
> Fixes: fd67e9c6ed5a ("drm/tegra: Do not implement runtime PM")
> Reported-by: Dmitry Osipenko <digetx@gmail.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
Hi,
This bug was originally reported by Paul Fertser, I redirected it to you.
Reported-by: Paul Fertser <fercerpav@gmail.com>
Formally, the stable kernel needs to be CCed since we want to have this
patch applied to the stable kernels.
Cc: stable@vger.kernel.org
Otherwise this is good to me, thank you!
Tested-by: Dmitry Osipenko <digetx@gmail.com>
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