Lines Matching full:msis
15 This guide describes the basics of Message Signaled Interrupts (MSIs),
18 try if a device doesn't support MSIs.
21 What are MSIs?
36 Why use MSIs?
39 There are three reasons why using MSIs can give an advantage over
45 a whole. MSIs are never shared, so this problem cannot arise.
54 Using MSIs avoids this problem as the interrupt-generating write cannot
61 MSIs, a device can support more interrupts, allowing each interrupt
69 How to use MSIs
74 support MSIs correctly, and for those machines, the APIs described below
77 Include kernel support for MSIs
186 Considerations when using MSIs
214 Several PCI chipsets or devices are known not to support MSIs.
215 The PCI stack provides three ways to disable MSIs:
221 Disabling MSIs globally
224 Some host chipsets simply don't support MSIs properly. If we're
226 FADT table. In this case, Linux automatically disables MSIs.
231 If you have a board which has problems with MSIs, you can pass pci=nomsi
232 on the kernel command line to disable MSIs on all devices. It would be
236 Disabling MSIs below a bridge
239 Some PCI bridges are not able to route MSIs between buses properly.
240 In this case, MSIs must be disabled on all devices behind the bridge.
242 Some bridges allow you to enable MSIs by changing some bits in their
245 Linux mostly knows about them and automatically enables MSIs if it can.
247 MSIs in configuration space using whatever method you know works, then
248 enable MSIs on that bridge by doing::
255 To disable MSIs, echo 0 instead of 1. Changing this value should be
262 Disabling MSIs on a single device
271 Finding why MSIs are disabled on a device
275 why MSIs may not be enabled for a given device. Your first step should
276 be to examine your dmesg carefully to determine whether MSIs are enabled
281 `/sys/bus/pci/devices/*/msi_bus` will tell you whether MSIs are enabled (1)
283 to bridges between the PCI root and the device, MSIs are disabled.
285 It is also worth checking the device driver to see whether it supports MSIs.