On Wed, 2018-07-18 at 09:53 +0200, Benjamin Tissoires wrote:

On Tue, Jul 17, 2018 at 10:06 PM Srinivas Pandruvada
[off-list ref] wrote:

quoted

On Mehlow Xeon-E workstation, ISH PCI device is enabled but without
ISH
firmware. Here the ISH device PCI device id was reused for some non
Linux
storage drivers. So this was not done for enabling ISH. But this
has a
undesirable side effect for Linux.

Here the ISH driver will be loaded via PCI enumeration and will try
to do
reset sequence. But reset sequence will wait till timeout as there
is no
real ISH firmware is present to take action. This delay will add to
boot
time of Linux (This platform will still continue to boot after this
timeout).

To avoid this boot delay we need to prevent loading of ISH drivers
on
this platform. So we need to have hack to avoid treating this
device as
ISH on this platform. To identify this workstation, we need some
runtime
method. Luckily there are special PCI id on this workstation to
distinguish from the client version of this platform. On client
version,
the ISH is supported using same PCI device id. So this change look
for
the presence of PCI device IDs A309 and A30A and exit.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel
.com>
---
This is not a change for 4.18-rc.

 drivers/hid/intel-ish-hid/ipc/pci-ish.c | 23
+++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/hid/intel-ish-hid/ipc/pci-ish.c

b/drivers/hid/intel-ish-hid/ipc/pci-ish.c
index a2c53ea3b5ed..d6e7156c36d9 100644

--- a/drivers/hid/intel-ish-hid/ipc/pci-ish.c
+++ b/drivers/hid/intel-ish-hid/ipc/pci-ish.c

@@ -95,6 +95,26 @@ static int ish_init(struct ishtp_device *dev)
        return 0;
 }

+
+static bool ish_invalid_firmware(void)
+{
+       struct pci_dev *pdev;
+
+       pdev = pci_get_device(PCI_VENDOR_ID_INTEL, 0xA309, NULL);
+       if (pdev) {
+               pci_dev_put(pdev);
+               return true;
+       }
+
+       pdev = pci_get_device(PCI_VENDOR_ID_INTEL, 0xA30A, NULL);
+       if (pdev) {
+               pci_dev_put(pdev);
+               return true;
+       }

I think this duplicated code should be merged in a for loop on an
array of blacklisted items :)

Good idea.

Thanks,
Srinivas

Cheers,
Benjamin

quoted

+
+       return false;
+}
+
 /**
  * ish_probe() - PCI driver probe callback
  * @pdev:      pci device

@@ -110,6 +130,9 @@ static int ish_probe(struct pci_dev *pdev,

const struct pci_device_id *ent)
        struct ish_hw *hw;
        int     ret;

+       if (ish_invalid_firmware())
+               return -ENODEV;
+
        /* enable pci dev */
        ret = pci_enable_device(pdev);
        if (ret) {
--
2.17.1