From: Thomas Gleixner Date: Tue, 13 Apr 2010 13:31:36 +0000 (+0200) Subject: x86, hpet: Restrict read back to affected ATI chipsets X-Git-Tag: v2.6.35-rc1~494^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=30a564be9d9554c168a654eddc2165869cc0d7bf;p=pandora-kernel.git x86, hpet: Restrict read back to affected ATI chipsets After programming the HPET, we do a readback as a workaround for ATI/SBx00 chipsets as a synchronization. Unfortunately this triggers an erratum in newer ICH chipsets (ICH9+) where reading the comparator immediately after the write returns the old value. Furthermore, as always, I/O reads are bad for performance. Therefore, restrict the readback to the chipsets that need it, or, for debugging purposes, when we are running with hpet=verbose. Signed-off-by: Thomas Gleixner Acked-by: Venkatesh Pallipadi LKML-Reference: <20100225185348.GA9674@linux-os.sc.intel.com> Signed-off-by: H. Peter Anvin --- Reading git-diff-tree failed