Modifying the Maximum Read Request Size to 0 (value of 128Bytes) has
massive negative ramifications on some devices. Without knowing which
devices have this issue, do not modify from the default value when
walking the PCI-E bus.
Signed-off-by: Jon Mason <mason@xxxxxxxx>
---
drivers/pci/probe.c | 36 ------------------------------------
1 files changed, 0 insertions(+), 36 deletions(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8473727..d896c5e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1394,41 +1394,6 @@ static void pcie_write_mps(struct pci_dev *dev, int mps)
dev_err(&dev->dev, "Failed attempting to set the MPS\n");
}
-static void pcie_write_mrrs(struct pci_dev *dev, int mps)
-{
- int rc, mrrs;
-
- if (pcie_bus_config == PCIE_BUS_PERFORMANCE) {
- int dev_mpss = 128 << dev->pcie_mpss;
-
- /* For Max performance, the MRRS must be set to the largest
- * supported value. However, it cannot be configured larger
- * than the MPS the device or the bus can support. This assumes
- * that the largest MRRS available on the device cannot be
- * smaller than the device MPSS.
- */
- mrrs = mps < dev_mpss ? mps : dev_mpss;
- } else
- /* In the "safe" case, configure the MRRS for fairness on the
- * bus by making all devices have the same size
- */
- mrrs = mps;
-
-
- /* MRRS is a R/W register. Invalid values can be written, but a
- * subsiquent read will verify if the value is acceptable or not.
- * If the MRRS value provided is not acceptable (e.g., too large),
- * shrink the value until it is acceptable to the HW.
- */
- while (mrrs != pcie_get_readrq(dev) && mrrs >= 128) {
- rc = pcie_set_readrq(dev, mrrs);
- if (rc)
- dev_err(&dev->dev, "Failed attempting to set the MRRS\n");
-
- mrrs /= 2;
- }
-}
-
static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
{
int mps = 128 << *(u8 *)data;
@@ -1440,7 +1405,6 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));
pcie_write_mps(dev, mps);
- pcie_write_mrrs(dev, mps);
dev_info(&dev->dev, "Dev MPS %d MPSS %d MRRS %d\n",
pcie_get_mps(dev), 128<<dev->pcie_mpss, pcie_get_readrq(dev));
--
1.7.6
--
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