Hi Greg, On Thu, Oct 15, 2020 at 9:17 AM Ben Chuang <benchuanggli@xxxxxxxxx> wrote: > > Hi, Greg, > > On Wed, Oct 14, 2020 at 7:37 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > On Wed, Oct 14, 2020 at 06:42:06PM +0800, Ben Chuang wrote: > > > Hi Greg, > > > > > > On Wed, Oct 14, 2020 at 4:10 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > 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. > > > > > > Yes. > > > > It did? What kernel release from kernel.org did it work, and what > > kernel release did it break on? > > Sorry, I don't know if "this Hardware" refers to a single GL975x > controller or the whole system. > "Yes", for those existing systems built in GL975x controller. These > systems are no EMI issue on v5.4~v5.9. > > "No", for some systems with developing stage build in GL975x > controller because there may be an EMI issue. > For those systems, they need the v5.9 to pass the EMI test. > > > > > > > > > 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. > > > > > > With this definition, no. > > > > Wait, I do not understand, this is the exact oposite of what you said > > above. > > > > Which is true? > > These existing systems built with GL975x have no EMI problems. > The patch can reduce the impact of EMI, so these existing systems are still ok. > > For these existing systems, on an older kernel (v5.4) they work fine > (no EMI issue), on a newer kernel (v5.9) they work fine (no EMI > issue). > For those developing systems, on an older kernel (v5.4) they don't > work fine (EMI issue), on a newer kernel (v5.9) they work fine(no EMI > issue). > Sorry, I forgot to consider some existing machines with pre-installed windows. These machines fit the definition of regression. They will have EMI issue when v5.4 is installed on them. Best regards, Ben > > > > totally confused, > > If you are still confused, please let me know. :). > > Best regards, > Ben > > > > > greg k-h
