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Diffstat (limited to 'results/scraper/launchpad-without-comments/1722857')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1722857 | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1722857 b/results/scraper/launchpad-without-comments/1722857 new file mode 100644 index 000000000..18c848950 --- /dev/null +++ b/results/scraper/launchpad-without-comments/1722857 @@ -0,0 +1,5 @@ +Missing PCI "programming interface" ID emulation for USB host controllers + +Qemu doesn't currently emulate the correct value of the "register level programming interface" field in the PCI config space of USB host controllers. As a result, some guest operating systems (most notably Windows) fail to load e.g. generic xHCI drivers, and instead ask for a vendor-specific driver, which may not be always available. + +Example: "-device nec-usb-xhci" emulates a Renesas (formerly NEC) uPD720202 xHCI controller. However, in the PCI config space, it shows us as class 0C, subclass 03, prog-if 00 (UHCI) where as the real uPD720202 (and all real xHCI controllers) have prog-if 30 (xHCI). A Windows guest booted with this option will not recognize devices attached to the XHCI controller unless drivers from Renesas are manually installed first, even though recent Windows versions include a generic xHCI driver that works perfectly well with real uPD720202 hardware. \ No newline at end of file |