svn commit: r352362 - stable/12/sys/dev/ichiic

[Vladimir Kondratyev]

Author: wulf
Date: Sun Sep 15 19:16:42 2019
New Revision: 352362
URL: https://svnweb.freebsd.org/changeset/base/352362

Log:
  ig4(4): Fix SDA HOLD time set too low on Skylake controllers
  
  Execution of "Soft reset" command (IG4_REG_RESETS_SKL) at controller init
  stage sets SDA_HOLD register value to 0x0001 which is often too low for
  normal operation.
  
  Set SDA_HOLD back to 28 after reset to restore controller functionality.
  
  PR:		240339
  Reported by:	imp, GregV, et al.

Modified:
  stable/12/sys/dev/ichiic/ig4_iic.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/dev/ichiic/ig4_iic.c
==============================================================================
--- stable/12/sys/dev/ichiic/ig4_iic.c	Sun Sep 15 18:29:45 2019	(r352361)
+++ stable/12/sys/dev/ichiic/ig4_iic.c	Sun Sep 15 19:16:42 2019	(r352362)
@@ -590,6 +590,8 @@ ig4iic_attach(ig4iic_softc_t *sc)
 	reg_write(sc, IG4_REG_SS_SCL_LCNT, 125);
 	reg_write(sc, IG4_REG_FS_SCL_HCNT, 100);
 	reg_write(sc, IG4_REG_FS_SCL_LCNT, 125);
+	if (sc->version == IG4_SKYLAKE)
+		reg_write(sc, IG4_REG_SDA_HOLD, 28);
 
 	/*
 	 * Use a threshold of 1 so we get interrupted on each character,