From b2f9239e03d3c6dcdff77da70d7578ff7a4fa0af Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Fri, 19 Mar 2021 08:06:37 +0100 Subject: [PATCH] UPSTREAM: drm/tegra: dc: Restore coupling of display controllers 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. Change-Id: I74817efbdb2afa6f775ad9b8d1657496f4c5626b Fixes: fd67e9c6ed5a ("drm/tegra: Do not implement runtime PM") Reported-by: Dmitry Osipenko Reported-by: Paul Fertser Tested-by: Dmitry Osipenko Signed-off-by: Thierry Reding Signed-off-by: Jon Hunter Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2545938 Reviewed-by: svc_kernel_abi Reviewed-by: Mikko Perttunen Reviewed-by: mobile promotions Tested-by: mobile promotions GVS: Gerrit_Virtual_Submit --- 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 f964808c..dff65df6 100644 --- a/drivers/gpu/drm/tegra/dc.c +++ b/drivers/gpu/drm/tegra/dc.c @@ -2577,22 +2577,18 @@ 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;