Messages in this thread |  | | Date | Tue, 3 Apr 2018 09:05:52 -0500 | From | Bjorn Helgaas <> | Subject | Re: [PATCH v5 03/14] PCI: Add pcie_bandwidth_capable() to compute max supported link bandwidth |
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On Mon, Apr 02, 2018 at 05:30:54PM -0700, Jacob Keller wrote: > On Mon, Apr 2, 2018 at 7:05 AM, Bjorn Helgaas <helgaas@kernel.org> wrote: > > +/* PCIe speed to Mb/s reduced by encoding overhead */ > > +#define PCIE_SPEED2MBS_ENC(speed) \ > > + ((speed) == PCIE_SPEED_16_0GT ? (16000*(128/130)) : \ > > + (speed) == PCIE_SPEED_8_0GT ? (8000*(128/130)) : \ > > + (speed) == PCIE_SPEED_5_0GT ? (5000*(8/10)) : \ > > + (speed) == PCIE_SPEED_2_5GT ? (2500*(8/10)) : \ > > + 0) > > + > > Should this be "(speed * x ) / y" instead? wouldn't they calculate > 128/130 and truncate that to zero before multiplying by the speed? Or > are compilers smart enough to do this the other way to avoid the > losses?
Yep, thanks for saving me yet more embarrassment.
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