[Linux1394-cvslog] rev 657 - trunk

[SVN U. <dm...@li...>]

Author: dmaas
Date: 2002-10-28 22:19:41 -0500 (Mon, 28 Oct 2002)
New Revision: 657

Modified:
   trunk/raw1394.c
Log:
rawiso merge part 5 - last one - change raw1394 poll() to return POLLPRI for isochronous activity. There is a slight chance this could break some existing applications - if they (incorrectly) assume that POLLPRI or an exception return from select() means there are pending read events, they could end up stuck in raw1394_loop_iterate(). If that happens, we need to find another way to signal isochronous activity.

Modified: trunk/raw1394.c
==============================================================================
--- trunk/raw1394.c	(original)
+++ trunk/raw1394.c	2002-10-28 22:19:42.000000000 -0500
@@ -2157,6 +2157,15 @@
 	return -EINVAL;
 }
 
+/* Queued read() events and isochronous readiness are two completely
+ * independent sources of input. We must provide unique POLL values
+ * for each, so that libraw can distinguish between them. Older versions
+ * of libraw expect POLLIN to mean only that a read() event is pending.
+ * So, we have to use something other than POLLIN. The best choice seems
+ * to be POLLPRI ("urgent out-of-band input") - which also allows us
+ * to support select(), since POLLPRI signals "exception" activity
+ */
+
 static unsigned int raw1394_poll(struct file *file, poll_table *pt)
 {
         struct file_info *fi = file->private_data;
@@ -2164,12 +2173,19 @@
 
         poll_wait(file, &fi->poll_wait_complete, pt);
 
+	/* check for pending read() events */
         spin_lock_irq(&fi->reqlists_lock);
         if (!list_empty(&fi->req_complete)) {
                 mask |= POLLIN | POLLRDNORM;
         }
         spin_unlock_irq(&fi->reqlists_lock);
 
+	/* check for isochronous activity */
+	if(fi->iso_state != RAW1394_ISO_INACTIVE) {
+		if(hpsb_iso_n_ready(fi->iso_handle) > 0)
+			mask |= POLLPRI;
+	}
+	
         return mask;
 }