RE: [PATCH 3/4] hid: intel-ish-hid: ipc: Fix driver reinit failure

-----Original Message-----
From: Srinivas Pandruvada [mailto:srinivas.pandruvada@linux.intel.com]
Sent: Sunday, October 16, 2016 12:23 AM
To: jikos@kernel.org
Cc: linux-input@vger.kernel.org; Xu, Even <even.xu@intel.com>
Subject: [PATCH 3/4] hid: intel-ish-hid: ipc: Fix driver reinit failure

From: Even Xu <even.xu@intel.com>

When built as a module, modprobe followed by rmmod can fail because DMA
was still active. So to fix this, DMA needs to be disabled during module exit.

This change disables DMA during modules exit and change the ISH PCI device
status to D3.

Signed-off-by: Even Xu <even.xu@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/hid/intel-ish-hid/ipc/ipc.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/hid/intel-ish-hid/ipc/ipc.c b/drivers/hid/intel-ish-hid/ipc/ipc.c
index 0e0dfa6..66c6755 100644
--- a/drivers/hid/intel-ish-hid/ipc/ipc.c
+++ b/drivers/hid/intel-ish-hid/ipc/ipc.c

@@ -905,6 +905,26 @@ struct ishtp_device *ish_dev_init(struct pci_dev *pdev)
  */
 void	ish_device_disable(struct ishtp_device *dev)
 {
+	struct pci_dev *pdev = dev->pdev;
+	uint16_t csr;
+
+	if (!pdev)
+		return;
+
+	/* Disable dma communication between FW and host */
+	if (ish_disable_dma(dev)) {
+		dev_err(&pdev->dev,
+			"Can't reset - stuck with DMA in-progress\n");
+		return;
+	}
+

+	/* Put ISH to D3 state for power saving */
+	pci_read_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL, &csr);
+
+	csr &= ~PCI_PM_CTRL_STATE_MASK;
+	csr |= PCI_D3hot;
+	pci_write_config_word(pdev, pdev->pm_cap + PCI_PM_CTRL, csr);
+