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Description
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These fixes from Xorg community head should be imported to the Solaris Xorg tree.
Henry tested them and reported:
I just tried this fix for libddc.so on my old CRT monitor
ViewSonic P815, and i2c probing succeeded !
With previous version of libddc (without the fix) i2c probing
was unreliable (mostly failure) and I had to use VBE probing
as fallback.
diff-tree 720f302d241e88e6e9f2962207da1aa9a79728b7 (from b5a8a71e64c76b8dd42962cbd7984215c6ce4aa8)
Author: Keith Packard < xxxxx@xxxxx.com>
Date: Sat Mar 17 20:14:05 2007 -0700
Slow down DDC I2C bus using a RiseFallTime of 20us for old monitors.
This time value makes the bus run slowly enough for even the least reliable
of monitors. Thanks to Pavel Troller for finding the necessary change.
diff --git a/hw/xfree86/ddc/xf86DDC.c b/hw/xfree86/ddc/xf86DDC.c
index 0f24c52..8080c8d 100644
--- a/hw/xfree86/ddc/xf86DDC.c
+++ b/hw/xfree86/ddc/xf86DDC.c
@@ -337,6 +337,12 @@ DDCRead_DDC2(int scrnIndex, I2CBusPtr pB
unsigned char *R_Buffer;
int i;
+ /*
+ * Slow down the bus so that older monitors don't
+ * miss things.
+ */
+ pBus->RiseFallTime = 20;
+
if (!(dev = xf86I2CFindDev(pBus, 0x00A0))) {
dev = xf86CreateI2CDevRec();
dev->DevName = "ddc2";
diff-tree b5a8a71e64c76b8dd42962cbd7984215c6ce4aa8 (from 2489dae9f7def788910eee5733931392df83a0d6)
Author: Keith Packard < xxxxx@xxxxx.com>
Date: Sat Mar 17 17:26:11 2007 -0700
Remove extra (and wrong) I2C ByteTimeout setting in DDC code.
The DDC code sets the I2C timeouts to VESA standards, except that it had an
extra setting of the ByteTimeout value which was wrong (off by a factor of
50). Removing this should help DDC work on many more monitors. Note that the
Intel driver duplicated these settings, along with the error. Yay for cult
and paste coding.
diff --git a/hw/xfree86/ddc/xf86DDC.c b/hw/xfree86/ddc/xf86DDC.c
index 4ce585c..0f24c52 100644
--- a/hw/xfree86/ddc/xf86DDC.c
+++ b/hw/xfree86/ddc/xf86DDC.c
@@ -344,7 +344,6 @@ DDCRead_DDC2(int scrnIndex, I2CBusPtr pB
dev->ByteTimeout = 2200; /* VESA DDC spec 3 p. 43 (+10 %) */
dev->StartTimeout = 550;
dev->BitTimeout = 40;
- dev->ByteTimeout = 40;
dev->AcknTimeout = 40;
dev->pI2CBus = pBus;
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