Iofixes #9
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Iofixes #9
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The wakelock avare evdev drivers hold a wakelock only until all clients have read all events. If buffered reads are used, we might hit automatic suspend before having chance to obtain user space wakelock for the duration of actually processing the input.
Makes issues we might have easier to spot
Looks like glib assumes that all regular, characted device and block device files are seekable. This produces lots of false positives in case of MCE inputs.
Should improve performance since a amaller number of mainloop .. callback roundtrips are needed. Also allows us to skip at least some the input we are not interested in even if seeking the underlying file descriptor is not possible.
| /** | ||
| * Check if the monitored io channel is truly seekable | ||
| * | ||
| * Glib seems to be making guesses based on file type and |
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I wonder if this is worth patching glib for, in case other components have a similar problem (now, or in the future). It also strikes me that this may be an issue that upstream might want to know about, so it might be nice to send a bugreport to them?
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Bug report is here:
https://bugzilla.gnome.org/show_bug.cgi?id=689075
Oops, copy paste error slipped through ...
spiiroin
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Nov 26, 2012
Fixes to io callbacks handling chunked inputs
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MCE (and glib) incorrectly assume that lseek() works with various device files. While seeking in
/dev/input/eventX files has never been possible, older kernels (for example 2.6.32) do not report lseek() errors. By lucky chance the fact that mce is using buffered reads hides most of the problems this might cause.
However, if kernel is recent enough to return ESPIPE when seek in evdev file is attempted, the touchscreen event skipping logic in mce starts to misbehave.
Also using buffered reads might cause broken wakelock chains when recovering from suspend due to power key press.
Signed-off-by: Simo Piiroinen simo.piiroinen@jollamobile.com