On Wed, Oct 14, 2020 at 04:00:49PM +0800, Ben Chuang wrote: > Hi Greg, > > On Tue, Oct 13, 2020 at 9:48 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > On Tue, Oct 13, 2020 at 07:11:13PM +0800, Ben Chuang wrote: > > > On Tue, Oct 13, 2020 at 4:57 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > On Tue, Oct 13, 2020 at 04:33:38PM +0800, Ben Chuang wrote: > > > > > On Tue, Oct 13, 2020 at 4:00 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > > > > On Tue, Oct 13, 2020 at 03:46:00PM +0800, Ben Chuang wrote: > > > > > > > From: Ben Chuang <ben.chuang@xxxxxxxxxxxxxxxxxxx> > > > > > > > > > > > > > > commit 786d33c887e15061ff95942db68fe5c6ca98e5fc upstream. > > > > > > > > > > > > > > Set SDR104's clock to 205MHz and enable SSC for GL9750 and GL9755 > > > > > > > > > > > > > > Signed-off-by: Ben Chuang <ben.chuang@xxxxxxxxxxxxxxxxxxx> > > > > > > > Link: https://lore.kernel.org/r/20200717033350.13006-1-benchuanggli@xxxxxxxxx > > > > > > > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > > > > > > Cc: <stable@xxxxxxxxxxxxxxx> # 5.4.x > > > > > > > --- > > > > > > > Hi Greg and Sasha, > > > > > > > > > > > > > > The patch is to improve the EMI of the hardware. > > > > > > > So it should be also required for some hardware devices using the v5.4. > > > > > > > Please tell me if have other questions. > > > > > > > > > > > > This looks like a "add support for new hardware" type of patch, right? > > > > > > > > > > No, this is for a mass production hardware. > > > > > > > > That does not make sense, sorry. > > > > > > > > Is this a bug that is being fixed, did the hardware work properly before > > > > 5.4 and now it does not? Or has it never worked properly and 5.9 is the > > > > first kernel that it now works on? > > > > > > It seems there is misunderstanding regarding “hardware” means. > > > I originally thought that the "hardware" refers to GL975x chips. > > > > > > This Genesys patch is to fix the EMI problem for GL975x controller on a system. > > > > Did it work on the 4.19 kernel? Another older kernel? Or is 5.9 the > > first kernel release where it works? > > The patch works on after v5.4. You are not answering the question I am trying to ask. My question is: Did this hardware ever work properly before the 5.9 kernel release. > > In other words, is this fixing a regression, or just enabling hardware > > support for something that has never worked before for this hardware? > > This patch is to reduce the EMI at SDR104 mode for GL975x. > It changes the preset frequency of SDR104 to 205Mhz and sets the SSC value. > So I think it is fixing a regression. A regression is when an older kernel works fine, but a newer kernel does not. When that happens, you can point to a specific commit and say, "this commit here broke this previously working hardware". Is that the case here? If not, this is not a regression. thanks, greg k-h
