[PATCHv5 2/2] parport: parport_pc: Implement architecture and device check to cut off false-positives

From: matwey
Date: Wed Aug 27 2014 - 04:10:01 EST

From: "Matwey V. Kornilov" <matwey@xxxxxxxxxx>

We definitely know that only x86 (32-bit) architecture is affected by the issue, so implement a stub instead of the actual check for other architectures.

We also know that motherboard LPT chipset is affected, so the port is either come from
parport_pc_init (when `io' module param is used) or
parport_pc_find_isa_ports (when default LPT ports are probbed: 0x378, 0x278, 0x3bc).
In both cases the port considered as 'legacy' and `dev' member of struct parport is NULL. See also comments for `struct parport' in parport.h

Signed-off-by: Matwey V. Kornilov <matwey@xxxxxxxxxx>
drivers/parport/parport_pc.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/parport/parport_pc.c b/drivers/parport/parport_pc.c
index fedc06b..5b27747 100644
--- a/drivers/parport/parport_pc.c
+++ b/drivers/parport/parport_pc.c
@@ -1702,7 +1702,8 @@ static int parport_ECP_supported(struct parport *pb)

-static int intel_bug_present(struct parport *pb)
+#ifdef CONFIG_X86_32
+static int intel_bug_present_check_epp(struct parport *pb)
const struct parport_pc_private *priv = pb->private_data;
int bug_present = 0;
@@ -1725,6 +1726,21 @@ static int intel_bug_present(struct parport *pb)

return bug_present;
+static int intel_bug_present(struct parport *pb)
+/* Check whether the device is legacy, not PCI or PCMCIA. Only legacy is known to be affected. */
+ if (pb->dev != NULL) {
+ return 0;
+ }
+ return intel_bug_present_check_epp(pb);
+static int intel_bug_present(struct parport *pb)
+ return 0;
+#endif /* CONFIG_X86_32 */

static int parport_ECPPS2_supported(struct parport *pb)

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