On Friday 18 July 2014, mat...@sai.msu.ru wrote:
> From: "Matwey V. Kornilov" <mat...@sai.msu.ru>
>
> The code in intel_bug_present is known to produce much false-positives.
> It is believed that the affected by the bug hardware are used with either
> Intel 80486 or Pentium.
>
> Perform the check only when the kernel configured as CONFIG_X86_32,
> then use cpuinfo_x86 of the first available CPU to check the model
> and run initial check code.
>
> Suggested-by: One Thousand Gnomes <gno...@lxorguk.ukuu.org.uk>
> Tested-by: Heiko Andreas Sommer <hsom...@eso.org>
> Signed-off-by: Matwey V. Kornilov <mat...@sai.msu.ru>
> ---
> drivers/parport/parport_pc.c | 21 ++++++++++++++++++++-
> 1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/parport/parport_pc.c b/drivers/parport/parport_pc.c
> index a6eaafb..6b28f9f 100644
> --- a/drivers/parport/parport_pc.c
> +++ b/drivers/parport/parport_pc.c
> @@ -65,6 +65,7 @@
> #include <linux/parport_pc.h>
> #include <linux/via.h>
> #include <asm/parport.h>
> +#include <asm/processor.h>
>
> #define PARPORT_PC_MAX_PORTS PARPORT_MAX
>
> @@ -1702,7 +1703,11 @@ static int parport_ECP_supported(struct parport *pb)
> }
> #endif
>
> -static int intel_bug_present(struct parport *pb)
> +/* It is believed that CPU model correlates with buggy LPT chipset model.
> + Here we check that or CPU is elder than Pentium Pro: either 80486 or
> Pentium. + If it is then we perform The Check. */
> +#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 +1730,20 @@ static int intel_bug_present(struct parport *pb)
>
> return bug_present;
> }
> +static int intel_bug_present(struct parport *pb)
> +{
> + struct cpuinfo_x86 *c = &cpu_data(0);
> +
> + if (c->x86_vendor == X86_VENDOR_INTEL && (c->x86 == 4 || c->x86 == 5))
> + return intel_bug_present_check_epp(pb);
You can have a non-Intel CPU in a 486 or Pentium board.
> + return 0;
> +}
> +#else
> +static int intel_bug_present(struct parport *pb)
> +{
> + return 0;
> +}
> +#endif
>
> static int parport_ECPPS2_supported(struct parport *pb)
> {
--
Ondrej Zary
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