Bug 1668875 Comment 10 Edit History

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(In reply to Chris Peterson [:cpeterson] from comment #9)
> > > Oh wow, and the parent process seems stuck in some a11y code under GetProxiedAccessibleInSubtree for a huge time.
> @ Jamie, do you know why the parent process might hang in `GetProxiedAccessibleInSubtree`?

That very likely means an a11y client asked for an Accessible, but the target content process is blocked. The hard part to figure out here is whether that's because a11y is slow or whether that's a symptom of non-a11y blocking in the content process. My guess is the latter (because otherwise we'd see long a11y calls in the content process profile), but that unfortunately means we end up with jank in the parent process (because some a11y client happened to query for something while the content process was busy).

> Does a Windows laptop with a touch screen enable a11y support in Firefox?

It seems to in some cases, especially on Surface machines. We have code to block this, but it either doesn't work any more or it doesn't work on certain devices. See bug 1531537, bug 1626789.
(In reply to Chris Peterson [:cpeterson] from comment #9)
> > > Oh wow, and the parent process seems stuck in some a11y code under GetProxiedAccessibleInSubtree for a huge time.
>
> @ Jamie, do you know why the parent process might hang in `GetProxiedAccessibleInSubtree`?

That very likely means an a11y client asked for an Accessible, but the target content process is blocked. The hard part to figure out here is whether that's because a11y is slow or whether that's a symptom of non-a11y blocking in the content process. My guess is the latter (because otherwise we'd see long a11y calls in the content process profile), but that unfortunately means we end up with jank in the parent process (because some a11y client happened to query for something while the content process was busy).

> Does a Windows laptop with a touch screen enable a11y support in Firefox?

It seems to in some cases, especially on Surface machines. We have code to block this, but it either doesn't work any more or it doesn't work on certain devices. See bug 1531537, bug 1626789.

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