Am 08.08.19 um 01:01 schrieb Bjorn Helgaas:
On Fri, Jul 26, 2019 at 12:55:52AM +0530, Sumit Saxena wrote:
In Resize BAR control register, bits[8:12] represents size of BAR. As per PCIe specification, below is encoded values in register bits to actual BAR size table:
Bits BAR size 0 1 MB 1 2 MB 2 4 MB 3 8 MB --
For 1 MB BAR size, BAR size bits should be set to 0 but incorrectly these bits are set to "1f". Latest megaraid_sas and mpt3sas adapters which support Resizable BAR with 1 MB BAR size fails to initialize during system resume from S3 sleep.
Fix: Correctly calculate BAR size bits for Resize BAR control register.
V2: -Simplified calculation of BAR size bits as suggested by Christian Koenig.
CC: stable@vger.kernel.org # v4.16+ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203939 Fixes: d3252ace0bc652a1a244455556b6a549f969bf99 ("PCI: Restore resized BAR state on resume") Signed-off-by: Sumit Saxena sumit.saxena@broadcom.com
drivers/pci/pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 29ed5ec1ac27..e59921296125 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1438,7 +1438,7 @@ static void pci_restore_rebar_state(struct pci_dev *pdev) pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl); bar_idx = ctrl & PCI_REBAR_CTRL_BAR_IDX; res = pdev->resource + bar_idx;
size = order_base_2((resource_size(res) >> 20) | 1) - 1;
size = order_base_2(resource_size(res) >> 20);Since BAR sizes are always powers of 2, wouldn't this be simpler as:
size = ilog2(resource_size(res)) - 20;which nicely matches the table in PCIe r5.0, sec 7.8.6.3?
Yeah, that should obviously work as well.
We would have a serious problem in the resource management if the resource size is smaller than 1MB or not a power of two.
Feel free to add my r-b.
Regards, Christian.
ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE; ctrl |= size << PCI_REBAR_CTRL_BAR_SHIFT; pci_write_config_dword(pdev, pos + PCI_REBAR_CTRL, ctrl);-- 2.18.1