6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Qian commit 51c2db3ef0cb89a49ab7f47a40efd5d5b074ce8d upstream. On i.MX8MP the VPU blk-ctrl exposes G1, G2 and VC8000E as three separate genpds, each serialized only by its own genpd lock, so their power_on and power_off callbacks can run concurrently on SMP. The sequences are not independent: they share the VPUMIX bus domain, the VPU_NOC and the ADB400 handshake. On power up the GPC cannot ack-verify the ADB400 handshake - the ack only completes once blk-ctrl sets the bus clk-en bit - so it just waits a fixed delay instead of polling hskack. A sibling transition landing inside another domain's reset window disturbs that shared clock and handshake timing, the victim's reset does not take effect, and its block registers read back all zeros: the decoder times out or the encoder fails its format check. Serialize the blk-ctrl reset sequence with a per-blk-ctrl mutex; the driver deliberately avoids a genpd hierarchy, so the genpd core gives no cross-sibling serialization. Fixes: a1a5f15f7f6c ("soc: imx: imx8m-blk-ctrl: add i.MX8MP VPU blk ctrl") Signed-off-by: Ming Qian Reviewed-by: Frank Li Cc: stable@vger.kernel.org Signed-off-by: Ulf Hansson Signed-off-by: Greg Kroah-Hartman --- drivers/pmdomain/imx/imx8m-blk-ctrl.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) --- a/drivers/pmdomain/imx/imx8m-blk-ctrl.c +++ b/drivers/pmdomain/imx/imx8m-blk-ctrl.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -34,6 +35,12 @@ struct imx8m_blk_ctrl { struct regmap *regmap; struct imx8m_blk_ctrl_domain *domains; struct genpd_onecell_data onecell_data; + /* + * Serializes the blk-ctrl reset/clock sequence across sibling domains; + * their transitions interact through the shared VPUMIX bus domain, + * VPU_NOC and the not-ack-verified ADB400 handshake (ERR050531). + */ + struct mutex power_lock; }; struct imx8m_blk_ctrl_domain_data { @@ -98,6 +105,8 @@ static int imx8m_blk_ctrl_power_on(struc struct imx8m_blk_ctrl *bc = domain->bc; int ret; + guard(mutex)(&bc->power_lock); + /* make sure bus domain is awake */ ret = pm_runtime_get_sync(bc->bus_power_dev); if (ret < 0) { @@ -164,6 +173,8 @@ static int imx8m_blk_ctrl_power_off(stru const struct imx8m_blk_ctrl_domain_data *data = domain->data; struct imx8m_blk_ctrl *bc = domain->bc; + guard(mutex)(&bc->power_lock); + /* put devices into reset and disable clocks */ if (data->mipi_phy_rst_mask) regmap_clear_bits(bc->regmap, BLK_MIPI_RESET_DIV, data->mipi_phy_rst_mask); @@ -202,6 +213,10 @@ static int imx8m_blk_ctrl_probe(struct p bc->dev = dev; + ret = devm_mutex_init(dev, &bc->power_lock); + if (ret) + return ret; + bc_data = of_device_get_match_data(dev); base = devm_platform_ioremap_resource(pdev, 0);