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PCI: pciehp: change wait time for valid configuration access

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Naoki Yanagimoto reported that configuration read on some hot-added
PCIe device returns invalid value. This patch fixes this problem.

According to the PCIe spec, software must wait for at least 1 second
to judge if the hot-added device is broken after Data Link Layer State
Changed Event. This patch changes pciehp driver to wait for 1 second
after the Data Link Layer State Changed Event is detected before
initiating a configuration access instead of 100 ms.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Tested-by: Naoki Yanagimoto <yanagimoto@np.css.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Kenji Kaneshige
2011-07-11 10:15:45 +09:00
committed by Jesse Barnes
parent 9b373ed18f
commit 0cab0841dc
2 changed files with 5 additions and 9 deletions
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11
drivers/pci/hotplug/pciehp_hpc.c
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@@ -275,16 +275,9 @@ int pciehp_check_link_status(struct controller *ctrl)
* hot-plug capable downstream port. But old controller might
* not implement it. In this case, we wait for 1000 ms.
*/
if (ctrl->link_active_reporting){
/* Wait for Data Link Layer Link Active bit to be set */
if (ctrl->link_active_reporting)
pcie_wait_link_active(ctrl);
/*
* We must wait for 100 ms after the Data Link Layer
* Link Active bit reads 1b before initiating a
* configuration access to the hot added device.
*/
msleep(100);
} else
else
msleep(1000);
retval = pciehp_readw(ctrl, PCI_EXP_LNKSTA, &lnk_status);