6.6-stable review patch. If anyone has any objections, please let me know.
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From: Diogo Ivo diogo.ivo@tecnico.ulisboa.pt
commit 660b299bed2a2a55a1f9102d029549d0235f881c upstream.
Commit b6bcbce33596 ("soc/tegra: pmc: Ensure power-domains are in a known state") was introduced so that all power domains get initialized to a known working state when booting and it does this by shutting them down (including asserting resets and disabling clocks) before registering each power domain with the genpd framework, leaving it to each driver to later on power its needed domains.
This caused the Google Pixel C to hang when booting due to a workaround in the DSI driver introduced in commit b22fd0b9639e ("drm/tegra: dsi: Clear enable register if powered by bootloader") meant to handle the case where the bootloader enabled the DSI hardware module. The workaround relies on reading a hardware register to determine the current status and after b6bcbce33596 that now happens in a powered down state thus leading to the boot hang.
Fix this by reverting b22fd0b9639e since currently we are guaranteed that the hardware will be fully reset by the time we start enabling the DSI module.
Fixes: b6bcbce33596 ("soc/tegra: pmc: Ensure power-domains are in a known state") Cc: stable@vger.kernel.org Signed-off-by: Diogo Ivo diogo.ivo@tecnico.ulisboa.pt Signed-off-by: Thierry Reding treding@nvidia.com Link: https://patch.msgid.link/20251103-diogo-smaug_ec_typec-v1-1-be656ccda391@tec... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/tegra/dsi.c | 9 --------- 1 file changed, 9 deletions(-)
--- a/drivers/gpu/drm/tegra/dsi.c +++ b/drivers/gpu/drm/tegra/dsi.c @@ -912,15 +912,6 @@ static void tegra_dsi_encoder_enable(str u32 value; int err;
- /* If the bootloader enabled DSI it needs to be disabled - * in order for the panel initialization commands to be - * properly sent. - */ - value = tegra_dsi_readl(dsi, DSI_POWER_CONTROL); - - if (value & DSI_POWER_CONTROL_ENABLE) - tegra_dsi_disable(dsi); - err = tegra_dsi_prepare(dsi); if (err < 0) { dev_err(dsi->dev, "failed to prepare: %d\n", err);