On Mon, Sep 25, 2023 at 12:40:34PM +0200, Konrad Dybcio wrote: > On 25.09.2023 12:37, Abel Vesa wrote: > > On 23-09-25 12:34:53, Konrad Dybcio wrote: > >> On 25.09.2023 12:33, Abel Vesa wrote: > >>> On 23-09-25 10:57:47, Konrad Dybcio wrote: > >>>> On 24.09.2023 18:07, Manivannan Sadhasivam wrote: > >>>>> PCIe Gen4 supports the interconnect bandwidth of 1969 MBps. So let's add > >>>>> the bandwidth support in the driver. Otherwise, the default bandwidth of > >>>>> 985 MBps will be used. > >>>>> > >>>>> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > >>>>> --- > >>>>> drivers/pci/controller/dwc/pcie-qcom.c | 7 +++++-- > >>>>> 1 file changed, 5 insertions(+), 2 deletions(-) > >>>>> > >>>>> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c > >>>>> index 297442c969b6..6853123f92c1 100644 > >>>>> --- a/drivers/pci/controller/dwc/pcie-qcom.c > >>>>> +++ b/drivers/pci/controller/dwc/pcie-qcom.c > >>>>> @@ -1384,11 +1384,14 @@ static void qcom_pcie_icc_update(struct qcom_pcie *pcie) > >>>>> case 2: > >>>>> bw = MBps_to_icc(500); > >>>>> break; > >>>>> + case 3: > >>>>> + bw = MBps_to_icc(985); > >>>>> + break; > >>>>> default: > >>>>> WARN_ON_ONCE(1); > >>>>> fallthrough; > >>>>> - case 3: > >>>>> - bw = MBps_to_icc(985); > >>>>> + case 4: > >>>>> + bw = MBps_to_icc(1969); > >>>>> break; > >>>> Are you adding case 4 under `default`? That looks.. bizzare.. > >>> > >>> That's intentional. You want it to use 1969MBps if there is a different > >>> gen value. AFAIU. > >> Gah right, then the commit message is wrong. > > > > Yep, should be: "Otherwise, the default bandwidth of 1969 MBps will be > > used." > > > > But maybe we should not default to that. Maybe we should still default > > to 985 MBps. > Perhaps we shouldn't have a default at all.. > > E.g. if the gen5 bus may get clogged if we exceed gen4 > limits > So the idea here is that if we happen to run this driver on a new Gen supported SoC, we have to let the user know that the interconnects are running at a lower gen speed and it needs attention. But I think we can simplify it by fixing a default bandwidth, say Gen3 and get rid of the fallthrough. And yeah, the same needs to be done for the pcie-qcom-ep driver as well. - Mani > Konrad -- மணிவண்ணன் சதாசிவம்
