On Sun, Feb 02, 2014 at 06:45:12PM +0100, Jean-Francois Moine wrote: > On Sun, 2 Feb 2014 16:23:09 +0000 > Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote: > > > On Sat, Jan 25, 2014 at 06:14:42PM +0100, Jean-Francois Moine wrote: > > > This patch takes care of the write-only registers of the tda998x. > > > > > > The registers SOFTRESET, TBG_CNTRL_0 and TBG_CNTRL_1 have all bits > > > cleared after reset, so, they may be fully re-written. > > > > > > The register MAT_CONTRL is set to > > > MAT_CONTRL_MAT_BP | MAT_CONTRL_MAT_SC(1) > > > after reset, so, it may be fully set again to this value. > > > > I said in v3 of this patch, which seems to remain unaddressed: > > > > > /* must be last register set: */ > > > - reg_clear(priv, REG_TBG_CNTRL_0, TBG_CNTRL_0_SYNC_ONCE); > > > + reg_write(priv, REG_TBG_CNTRL_0, 0); > > > > Register changes which have a potential effect shouldn't be part of a > > patch which is really only trying to avoid reading from write only > > registers. > > > > This could be a potential functional change - and it's probably one > > which Rob Clark should at least be made aware of. As I commented last > > time, when you're changing register values in an otherwise innocuous > > patch, you should comment about them in the patch description. > > According to the tda9983b documentation, the register TBG_CNTRL_0 is > set to 0 at reset time. I think that it is the same for all the tda998x > family. In the other hand, this register is supposed to be write only, > so reading it may return any value, and the reg_clear() function may > set any other bits. Then, clearing one bit is less secure than clearing > the full register. Okay, in that case I'm happy with this patch. -- FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad. Estimate before purchase was "up to 13.2Mbit". _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
