linux/drivers/usb/core/message.c

1726 lines
53 KiB

IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 14:55:46 +01:00
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 14:55:46 +01:00
USB: make usbdevices export their device nodes instead of using a separate class o The "real" usb-devices export now a device node which can populate /dev/bus/usb. o The usb_device class is optional now and can be disabled in the kernel config. Major/minor of the "real" devices and class devices are the same. o The environment of the usb-device event contains DEVNUM and BUSNUM to help udev and get rid of the ugly udev rule we need for the class devices. o The usb-devices and usb-interfaces share the same bus, so I used the new "struct device_type" to let these devices identify themselves. This also removes the current logic of using a magic platform-pointer. The name of the device_type is also added to the environment which makes it easier to distinguish the different kinds of devices on the same subsystem. It looks like this: add@/devices/pci0000:00/0000:00:1d.1/usb2/2-1 ACTION=add DEVPATH=/devices/pci0000:00/0000:00:1d.1/usb2/2-1 SUBSYSTEM=usb SEQNUM=1533 MAJOR=189 MINOR=131 DEVTYPE=usb_device PRODUCT=46d/c03e/2000 TYPE=0/0/0 BUSNUM=002 DEVNUM=004 This udev rule works as a replacement for usb_device class devices: SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", \ NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0644" Updated patch, which needs the device_type patches in Greg's tree. I also got a bugzilla assigned for this. :) https://bugzilla.novell.com/show_bug.cgi?id=250659 Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-03-13 15:59:31 +01:00
USB: make usbdevices export their device nodes instead of using a separate class o The "real" usb-devices export now a device node which can populate /dev/bus/usb. o The usb_device class is optional now and can be disabled in the kernel config. Major/minor of the "real" devices and class devices are the same. o The environment of the usb-device event contains DEVNUM and BUSNUM to help udev and get rid of the ugly udev rule we need for the class devices. o The usb-devices and usb-interfaces share the same bus, so I used the new "struct device_type" to let these devices identify themselves. This also removes the current logic of using a magic platform-pointer. The name of the device_type is also added to the environment which makes it easier to distinguish the different kinds of devices on the same subsystem. It looks like this: add@/devices/pci0000:00/0000:00:1d.1/usb2/2-1 ACTION=add DEVPATH=/devices/pci0000:00/0000:00:1d.1/usb2/2-1 SUBSYSTEM=usb SEQNUM=1533 MAJOR=189 MINOR=131 DEVTYPE=usb_device PRODUCT=46d/c03e/2000 TYPE=0/0/0 BUSNUM=002 DEVNUM=004 This udev rule works as a replacement for usb_device class devices: SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", \ NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0644" Updated patch, which needs the device_type patches in Greg's tree. I also got a bugzilla assigned for this. :) https://bugzilla.novell.com/show_bug.cgi?id=250659 Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-03-13 15:59:31 +01:00
USB: make usbdevices export their device nodes instead of using a separate class o The "real" usb-devices export now a device node which can populate /dev/bus/usb. o The usb_device class is optional now and can be disabled in the kernel config. Major/minor of the "real" devices and class devices are the same. o The environment of the usb-device event contains DEVNUM and BUSNUM to help udev and get rid of the ugly udev rule we need for the class devices. o The usb-devices and usb-interfaces share the same bus, so I used the new "struct device_type" to let these devices identify themselves. This also removes the current logic of using a magic platform-pointer. The name of the device_type is also added to the environment which makes it easier to distinguish the different kinds of devices on the same subsystem. It looks like this: add@/devices/pci0000:00/0000:00:1d.1/usb2/2-1 ACTION=add DEVPATH=/devices/pci0000:00/0000:00:1d.1/usb2/2-1 SUBSYSTEM=usb SEQNUM=1533 MAJOR=189 MINOR=131 DEVTYPE=usb_device PRODUCT=46d/c03e/2000 TYPE=0/0/0 BUSNUM=002 DEVNUM=004 This udev rule works as a replacement for usb_device class devices: SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", \ NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0644" Updated patch, which needs the device_type patches in Greg's tree. I also got a bugzilla assigned for this. :) https://bugzilla.novell.com/show_bug.cgi?id=250659 Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-03-13 15:59:31 +01:00
USB: make usbdevices export their device nodes instead of using a separate class o The "real" usb-devices export now a device node which can populate /dev/bus/usb. o The usb_device class is optional now and can be disabled in the kernel config. Major/minor of the "real" devices and class devices are the same. o The environment of the usb-device event contains DEVNUM and BUSNUM to help udev and get rid of the ugly udev rule we need for the class devices. o The usb-devices and usb-interfaces share the same bus, so I used the new "struct device_type" to let these devices identify themselves. This also removes the current logic of using a magic platform-pointer. The name of the device_type is also added to the environment which makes it easier to distinguish the different kinds of devices on the same subsystem. It looks like this: add@/devices/pci0000:00/0000:00:1d.1/usb2/2-1 ACTION=add DEVPATH=/devices/pci0000:00/0000:00:1d.1/usb2/2-1 SUBSYSTEM=usb SEQNUM=1533 MAJOR=189 MINOR=131 DEVTYPE=usb_device PRODUCT=46d/c03e/2000 TYPE=0/0/0 BUSNUM=002 DEVNUM=004 This udev rule works as a replacement for usb_device class devices: SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", \ NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0644" Updated patch, which needs the device_type patches in Greg's tree. I also got a bugzilla assigned for this. :) https://bugzilla.novell.com/show_bug.cgi?id=250659 Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-03-13 15:59:31 +01:00
USB: make usbdevices export their device nodes instead of using a separate class o The "real" usb-devices export now a device node which can populate /dev/bus/usb. o The usb_device class is optional now and can be disabled in the kernel config. Major/minor of the "real" devices and class devices are the same. o The environment of the usb-device event contains DEVNUM and BUSNUM to help udev and get rid of the ugly udev rule we need for the class devices. o The usb-devices and usb-interfaces share the same bus, so I used the new "struct device_type" to let these devices identify themselves. This also removes the current logic of using a magic platform-pointer. The name of the device_type is also added to the environment which makes it easier to distinguish the different kinds of devices on the same subsystem. It looks like this: add@/devices/pci0000:00/0000:00:1d.1/usb2/2-1 ACTION=add DEVPATH=/devices/pci0000:00/0000:00:1d.1/usb2/2-1 SUBSYSTEM=usb SEQNUM=1533 MAJOR=189 MINOR=131 DEVTYPE=usb_device PRODUCT=46d/c03e/2000 TYPE=0/0/0 BUSNUM=002 DEVNUM=004 This udev rule works as a replacement for usb_device class devices: SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", \ NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0644" Updated patch, which needs the device_type patches in Greg's tree. I also got a bugzilla assigned for this. :) https://bugzilla.novell.com/show_bug.cgi?id=250659 Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-03-13 15:59:31 +01:00
[PATCH] USB: Consider power budget when choosing configuration This patch (as609) changes the way we keep track of power budgeting for USB hubs and devices, and it updates the choose_configuration routine to take this information into account. (This is something we should have been doing all along.) A new field in struct usb_device holds the amount of bus current available from the upstream port, and the usb_hub structure keeps track of the current available for each downstream port. Two new rules for configuration selection are added: Don't select a self-powered configuration when only bus power is available. Don't select a configuration requiring more bus power than is available. However the first rule is #if-ed out, because I found that the internal hub in my HP USB keyboard claims that its only configuration is self-powered. The rule would prevent the configuration from being chosen, leaving the hub & keyboard unconfigured. Since similar descriptor errors may turn out to be fairly common, it seemed wise not to include a rule that would break automatic configuration unnecessarily for such devices. The second rule may also trigger unnecessarily, although this should be less common. More likely it will annoy people by sometimes failing to accept configurations that should never have been chosen in the first place. The patch also changes usbcore's reaction when no configuration is suitable. Instead of raising an error and rejecting the device, now the core will simply leave the device unconfigured. People can always work around such problems by installing configurations manually through sysfs. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-11-23 12:03:12 -05:00
USB: make usbdevices export their device nodes instead of using a separate class o The "real" usb-devices export now a device node which can populate /dev/bus/usb. o The usb_device class is optional now and can be disabled in the kernel config. Major/minor of the "real" devices and class devices are the same. o The environment of the usb-device event contains DEVNUM and BUSNUM to help udev and get rid of the ugly udev rule we need for the class devices. o The usb-devices and usb-interfaces share the same bus, so I used the new "struct device_type" to let these devices identify themselves. This also removes the current logic of using a magic platform-pointer. The name of the device_type is also added to the environment which makes it easier to distinguish the different kinds of devices on the same subsystem. It looks like this: add@/devices/pci0000:00/0000:00:1d.1/usb2/2-1 ACTION=add DEVPATH=/devices/pci0000:00/0000:00:1d.1/usb2/2-1 SUBSYSTEM=usb SEQNUM=1533 MAJOR=189 MINOR=131 DEVTYPE=usb_device PRODUCT=46d/c03e/2000 TYPE=0/0/0 BUSNUM=002 DEVNUM=004 This udev rule works as a replacement for usb_device class devices: SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", \ NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0644" Updated patch, which needs the device_type patches in Greg's tree. I also got a bugzilla assigned for this. :) https://bugzilla.novell.com/show_bug.cgi?id=250659 Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-03-13 15:59:31 +01:00