The Intel Panther Point chipsets contain an EHCI and xHCI host controller
that shares some number of skew-dependent ports. These ports can be
switched from the EHCI to the xHCI host (and vice versa) by a hardware MUX
that is controlled by registers in the xHCI PCI configuration space. The
USB 3.0 SuperSpeed terminations on the xHCI ports can be controlled
separately from the USB 2.0 data wires.
This switchover mechanism is there to support users who do a custom
install of certain non-Linux operating systems that don't have official
USB 3.0 support. By default, the ports are under EHCI, SuperSpeed
terminations are off, and USB 3.0 devices will show up under the EHCI
controller at reduced speeds. (This was more palatable for the marketing
folks than having completely dead USB 3.0 ports if no xHCI drivers are
available.) Users should be able to turn on xHCI by default through a
BIOS option, but users are happiest when they don't have to change random
BIOS settings.
This patch introduces a driver method to switchover the ports from EHCI to
xHCI before the EHCI driver finishes PCI enumeration. We want to switch
the ports over before the USB core has the chance to enumerate devices
under EHCI, or boot from USB mass storage will fail if the boot device
connects under EHCI first, and then gets disconnected when the port
switches over to xHCI.
Add code to the xHCI PCI quirk to switch the ports from EHCI to xHCI. The
PCI quirks code will run before any other PCI probe function is called, so
this avoids the issue with boot devices.
Another issue is with BIOS behavior during system resume from hibernate.
If the BIOS doesn't support xHCI, it may switch the devices under EHCI to
allow use of the USB keyboard, mice, and mass storage devices. It's
supposed to remember the value of the port routing registers and switch
them back when the OS attempts to take control of the xHCI host controller,
but we all know not to trust BIOS writers.
Make both the xHCI driver and the EHCI driver attempt to switchover the
ports in their PCI resume functions. We can't guarantee which PCI device
will be resumed first, so this avoids any race conditions. Writing a '1'
to an already set port switchover bit or a '0' to a cleared port switchover
bit should have no effect.
The xHCI PCI configuration registers will be documented in the EDS-level
chipset spec, which is not public yet. I have permission from legal and
the Intel chipset group to release this patch early to allow good Linux
support at product launch. I've tried to document the registers as much
as possible, so please let me know if anything is unclear.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
This patch moves the AMD PLL quirk code in OHCI/EHCI driver to pci-quirks.c,
and exports the functions to be used by xHCI driver later.
AMD PLL quirk disable the optional PM feature inside specific
SB700/SB800/Hudson-2/3 platforms under the following conditions:
1. If an isochronous device is connected to OHCI/EHCI/xHCI port and is active;
2. Optional PM feature that powers down the internal Bus PLL when the link is
in low power state is enabled.
Without AMD PLL quirk, USB isochronous stream may stutter or have breaks
occasionally, which greatly impair the performance of audio/video streams.
Currently AMD PLL quirk is implemented in OHCI and EHCI driver, and will be
added to xHCI driver too. They are doing similar things actually, so move
the quirk code to pci-quirks.c, which has several advantages:
1. Remove duplicate defines and functions in OHCI/EHCI (and xHCI) driver and
make them cleaner;
2. AMD chipset information will be probed only once and then stored.
Currently they're probed during every OHCI/EHCI initialization, move
the detect code to pci-quirks.c saves the repeat detect cost;
3. Build up synchronization among OHCI/EHCI/xHCI driver. In current
code, every host controller enable/disable PLL only according to
its own status, and may enable PLL while there is still isoc transfer on
other HCs. Move the quirk to pci-quirks.c prevents this issue.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alex He <alex.he@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This reverts commit b7d5b439b7.
It conflicts with commit baab93afc2 "USB:
EHCI: ASPM quirk of ISOC on AMD Hudson" and merging the two just doesn't
work properly.
Cc: Andiry Xu <andiry.xu@amd.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alex He <alex.he@amd.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch moves the AMD PLL quirk code in OHCI/EHCI driver to pci-quirks.c,
and exports the functions to be used by xHCI driver later.
AMD PLL quirk disable the optional PM feature inside specific
SB700/SB800/Hudson-2/3 platforms under the following conditions:
1. If an isochronous device is connected to OHCI/EHCI/xHCI port and is active;
2. Optional PM feature that powers down the internal Bus PLL when the link is
in low power state is enabled.
Without AMD PLL quirk, USB isochronous stream may stutter or have breaks
occasionally, which greatly impair the performance of audio/video streams.
Currently AMD PLL quirk is implemented in OHCI and EHCI driver, and will be
added to xHCI driver too. They are doing similar things actually, so move
the quirk code to pci-quirks.c, which has several advantages:
1. Remove duplicate defines and functions in OHCI/EHCI (and xHCI) driver and
make them cleaner;
2. AMD chipset information will be probed only once and then stored.
Currently they're probed during every OHCI/EHCI initialization, move
the detect code to pci-quirks.c saves the repeat detect cost;
3. Build up synchronization among OHCI/EHCI/xHCI driver. In current
code, every host controller enable/disable PLL only according to
its own status, and may enable PLL while there is still isoc transfer on
other HCs. Move the quirk to pci-quirks.c prevents this issue.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alex He <alex.he@amd.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch adds a header file with proper prototypes for two functions
in drivers/usb/host/pci-quirks.c.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Sarah Sharp