MdeModulePkg/XhciDxe: Fix Broken Timeouts #968
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2948 Timeouts in the XhciDxe driver are taking longer than expected due to the timeout loops not accounting for code execution time. As en example, 5 second timeouts have been observed to take around 36 seconds to complete. Use SetTimer and Create/CheckEvent from Boot Services to determine when timeout occurred. Cc: Jian J Wang <jian.j.wang@intel.com> Cc: Hao A Wu <hao.a.wu@intel.com> Cc: Ray Ni <ray.ni@intel.com> Signed-off-by: Patrick Henz <patrick.henz@hpe.com> Reviewed-by: Hao A Wu <hao.a.wu@intel.com>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
https://edk2.groups.io/g/devel/message/65543
https://bugzilla.tianocore.org/show_bug.cgi?id=2948
Cover-letter:
Timeouts in the XhciDxe driver are taking longer than expected due to the timeout loops not accounting for code execution time. As en example, 5 second timeouts have been observed to take around 36 seconds to complete.
Use SetTimer and Create/CheckEvent from Boot Services to determine when timeout occurred. This patch was tested using forced timeouts and print statements with QEmu as well as phycial hardware. The forced timeouts were implemented in code via static variables that guaranteed a timeout the first time the function with the broken timeout was called.
Example:
XhcExecTransfer (
.
.
)
{
.
.
static int do_once = 1; // test line
.
.
do {
Finished = XhcCheckUrbResult (Xhc, Urb);
if (do_once) Finished = 0; // test line
if (Finished) {
break;
}
gBS->Stall (XHC_1_MICROSECOND);
} while (EFI_ERROR(gBS->CheckEvent (TimeoutEvent)));
do_once = 0; // test line
Using this forced timeout approach the correct timeouts were observed on both hardware and in QEmu.
Similar broken timeout loops have been found in the Uhci and Ehci drivers. This patch does not fix those issues.
Commit message:
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2948
Timeouts in the XhciDxe driver are taking longer than
expected due to the timeout loops not accounting for
code execution time. As en example, 5 second timeouts
have been observed to take around 36 seconds to complete.
Use SetTimer and Create/CheckEvent from Boot Services to
determine when timeout occurred.
Cc: Jian J Wang jian.j.wang@intel.com
Cc: Hao A Wu hao.a.wu@intel.com
Cc: Ray Ni ray.ni@intel.com
Signed-off-by: Patrick Henz patrick.henz@hpe.com
Reviewed-by: Hao A Wu hao.a.wu@intel.com