Attachment 30705 Details for Bug 14109 – xf86EloReadInput(): fix xserver unresponsiveness during touch

[patch] xf86EloReadInput(): fix xserver unresponsiveness during touch

elo-no-slowdown.patch (text/plain), 2.04 KB, created by Michael Smith on 2009-10-26 13:28:36 UTC

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Creator: Michael Smith

Created: 2009-10-26 13:28:36 UTC

Size: 2.04 KB

patch

obsolete

>xf86EloReadInput(): fix xserver unresponsiveness during touch
>
>The fix for bug #14109 ensures all bytes are emptied from the OS buffer
>by looping until xf86WaitForInput returns 0.  This patch just changes
>the timeout from 1 millisecond to 0: we don't want the X server to block
>if there's no more serial data.
>
>It also removes the Vmin and Vtime options, which were making the calls
>to read() block until a complete 10-byte packet buffer could be filled.
>At 9600 bps, this could pause the X server for up to 9 ms. The code can
>already handle partial buffers, so all we have to do is get rid of the
>Vmin.
>
>Also, if xf86EloGetPacket() returns !Success, we should continue rather
>than break so the xf86WaitForInput call can decide whether to exit, in
>case there's more data in the buffer.
>
>Before the fix, glxgears was giving me about 390 FPS normally and down
>to 140 FPS when dragging an empty area of the touchscreen. Now it's
>basically unchanged when the touchscreen is in use (390 -> 385 FPS).
>
>--- xf86-input-elographics-1.2.3/src/xf86Elo.c.orig	2009-10-26 15:35:56.000000000 -0400
>+++ xf86-input-elographics-1.2.3/src/xf86Elo.c	2009-10-26 16:11:59.000000000 -0400
>@@ -421,15 +421,17 @@
> #endif
> 
>   DBG(4, ErrorF("Entering ReadInput\n"));
>+
>   /*
>-   * Try to get a packet.
>+   * Read bytes until there's no data left. We may have more or less than
>+   * one packet worth of data in the OS buffer.
>    */
>-  while (xf86WaitForInput(local->fd, ELO_MAX_WAIT/100) > 0) {
>+  do {
>       if(xf86EloGetPacket(priv->packet_buf,
> 		       &priv->packet_buf_p,
> 		       &priv->checksum,
> 		       local->fd) != Success)
>-          break;
>+          continue;
> 
>       /*
>        * Process only ELO_TOUCHs here.
>@@ -488,6 +490,7 @@
>                       (state == ELO_PRESS) ? "Press" : ((state == ELO_RELEASE) ? "Release" : "Stream")));
>       }
>   }
>+  while (xf86WaitForInput(local->fd, 0) > 0);  /* don't wait, just check */
> }
> 
> 
>@@ -1059,8 +1062,6 @@
>   "StopBits", "1",
>   "DataBits", "8",
>   "Parity", "None",
>-  "Vmin", "10",
>-  "Vtime", "1",
>   "FlowControl", "None",
>   NULL
> };

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Attachments on bug 14109: 16658 | 17158 | 17205 | 30705 | 32095

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