xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

PCI: pciehp: Track enable/disable status

Browse Source 
handle_button_press_event() currently determines whether the slot has
been turned on or off by looking at the Power Controller Control bit in
the Slot Control register.  This assumes that an attention button
implies presence of a power controller even though that's not mandated
by the spec.  Moreover the Power Controller Control bit is unreliable
when a power fault occurs (PCIe r4.0, sec 6.7.1.8).  This issue has
existed since the driver was introduced in 2004.

Fix by replacing STATIC_STATE with ON_STATE and OFF_STATE and tracking
whether the slot has been turned on or off.  This is also a required
ingredient to make pciehp resilient to missed events, which is the
object of an upcoming commit.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Lukas Wunner
2018-07-19 17:27:45 -05:00
committed by Bjorn Helgaas
parent 774d446b0f
commit 9590192f25
3 changed files with 35 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/pci/hotplug/pciehp_hpc.c
View File

@@ -761,12 +761,17 @@ void pcie_shutdown_notification(struct controller *ctrl)
static int pcie_init_slot(struct controller *ctrl)
{
struct pci_bus *subordinate = ctrl_dev(ctrl)->subordinate;
struct slot *slot;
slot = kzalloc(sizeof(*slot), GFP_KERNEL);
if (!slot)
return -ENOMEM;
down_read(&pci_bus_sem);
slot->state = list_empty(&subordinate->devices) ? OFF_STATE : ON_STATE;
up_read(&pci_bus_sem);
slot->ctrl = ctrl;
mutex_init(&slot->lock);
mutex_init(&slot->hotplug_lock);