[edk2-devel] [PATCH] MdeModulePkg/UsbBusDxe: On reset rebuild descriptor table

[Jeremy Linton]

During port reset, the device descriptors should be checked
before attempting to set an endpoint configuration.

In particular this fixes a crash due to
ASSERT(TrsRing != NULL) in XhcSyncTrsRing(). That crash
happens during error recovery on devices attached to XHCI
hosts. This is because the port disable clears and deallocats
all the EP data structures. When the port is reconfigured
without first requesting the EP descriptors,
XhcSetConfigCmd[64]() is not being called because the
NumConfigurations remains 0.

We could attempt to rebuild the EP descriptions directly
from the XHCI driver. OTOH, its probably good practice to
assure the device description is what we expect from within
the core USB subsystem during reset.

Signed-off-by: Jeremy Linton <jeremy.linton at arm.com>
---
 MdeModulePkg/Bus/Usb/UsbBusDxe/UsbBus.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbBus.c b/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbBus.c
index 4b4915c019..17bb691bf8 100644
--- a/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbBus.c
+++ b/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbBus.c
@@ -874,6 +874,14 @@ UsbIoPortReset (
   // is in CONFIGURED state.
   //
   if (Dev->ActiveConfig != NULL) {
+    Status = UsbBuildDescTable (Dev);
+
+    if (EFI_ERROR (Status)) {
+      DEBUG ((EFI_D_ERROR, "UsbIoPortReset: failed to build descriptor table for %d - %r\n",
+                 Dev->Address, Status));
+      goto ON_EXIT;
+    }
+
     Status = UsbSetConfig (Dev, Dev->ActiveConfig->Desc.ConfigurationValue);
 
     if (EFI_ERROR (Status)) {
-- 
2.24.1


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