This is a note to let you know that I've just added the patch titled staging: mt7621-pci: fix hang when nothing is connected to pcie ports to the 5.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: staging-mt7621-pci-fix-hang-when-nothing-is-connected-to-pcie-ports.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 7d761b084b3c785e1fbbe707fbdf7baba905c6ad Mon Sep 17 00:00:00 2001 From: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx> Date: Mon, 23 Aug 2021 19:08:03 +0200 Subject: staging: mt7621-pci: fix hang when nothing is connected to pcie ports From: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx> commit 7d761b084b3c785e1fbbe707fbdf7baba905c6ad upstream. When nothing is connected to pcie ports, each port is set to reset state. When this occurs, next access result in a hang on boot as follows: mt7621-pci 1e140000.pcie: pcie0 no card, disable it (RST & CLK) mt7621-pci 1e140000.pcie: pcie1 no card, disable it (RST & CLK) mt7621-pci 1e140000.pcie: pcie2 no card, disable it (RST & CLK) [ HANGS HERE ] Fix this just detecting 'nothing is connected state' to avoid next accesses to pcie port related configuration registers. Fixes: b99cc3a2b6b6 ("staging: mt7621-pci: avoid custom 'map_irq' function") Cc: stable <stable@xxxxxxxxxxxxxxx> Reported-by: DENG Qingfang <dqfext@xxxxxxxxx> Signed-off-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx> Link: https://lore.kernel.org/r/20210823170803.2108-1-sergio.paracuellos@xxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/staging/mt7621-pci/pci-mt7621.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) --- a/drivers/staging/mt7621-pci/pci-mt7621.c +++ b/drivers/staging/mt7621-pci/pci-mt7621.c @@ -56,6 +56,7 @@ #define PCIE_BAR_ENABLE BIT(0) #define PCIE_PORT_INT_EN(x) BIT(20 + (x)) #define PCIE_PORT_LINKUP BIT(0) +#define PCIE_PORT_CNT 3 #define PERST_DELAY_MS 100 @@ -388,10 +389,11 @@ static void mt7621_pcie_reset_ep_deasser msleep(PERST_DELAY_MS); } -static void mt7621_pcie_init_ports(struct mt7621_pcie *pcie) +static int mt7621_pcie_init_ports(struct mt7621_pcie *pcie) { struct device *dev = pcie->dev; struct mt7621_pcie_port *port, *tmp; + u8 num_disabled = 0; int err; mt7621_pcie_reset_assert(pcie); @@ -423,6 +425,7 @@ static void mt7621_pcie_init_ports(struc slot); mt7621_control_assert(port); port->enabled = false; + num_disabled++; if (slot == 0) { tmp = port; @@ -433,6 +436,8 @@ static void mt7621_pcie_init_ports(struc phy_power_off(tmp->phy); } } + + return (num_disabled != PCIE_PORT_CNT) ? 0 : -ENODEV; } static void mt7621_pcie_enable_port(struct mt7621_pcie_port *port) @@ -540,7 +545,11 @@ static int mt7621_pci_probe(struct platf return err; } - mt7621_pcie_init_ports(pcie); + err = mt7621_pcie_init_ports(pcie); + if (err) { + dev_err(dev, "Nothing connected in virtual bridges\n"); + return 0; + } err = mt7621_pcie_enable_ports(bridge); if (err) { Patches currently in stable-queue which might be from sergio.paracuellos@xxxxxxxxx are queue-5.14/staging-mt7621-pci-fix-hang-when-nothing-is-connected-to-pcie-ports.patch