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Message-ID: <CAErSpo7i+pZoPZWdJOLfJ4xJzs1NRVEmk1-N-NL+xK65coFZiA@mail.gmail.com>
Date: Fri, 9 Nov 2012 10:15:01 -0700
From: Bjorn Helgaas <bhelgaas@...gle.com>
To: Jingoo Han <jg1.han@...sung.com>
Cc: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
David Airlie <airlied@...ux.ie>,
dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] PCI: Fix bit definitions of PCI_EXP_LNKCAP2 register
On Thu, Nov 8, 2012 at 11:56 PM, Jingoo Han <jg1.han@...sung.com> wrote:
> According to the PCIe 3.0 spec, PCI_EXP_LNKCAP2_SLS_2_5GB is
> 1st bit of PCI_EXP_LNKCAP2 register, not 0th bit. So, the bit
> definition of supported link speed vector should be fixed.
>
> Signed-off-by: Jingoo Han <jg1.han@...sung.com>
> ---
> include/uapi/linux/pci_regs.h | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index 20ae747..14a3184 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -544,9 +544,9 @@
> #define PCI_EXP_OBFF_WAKE_EN 0x6000 /* OBFF using WAKE# signaling */
> #define PCI_CAP_EXP_ENDPOINT_SIZEOF_V2 44 /* v2 endpoints end here */
> #define PCI_EXP_LNKCAP2 44 /* Link Capability 2 */
> -#define PCI_EXP_LNKCAP2_SLS_2_5GB 0x01 /* Current Link Speed 2.5GT/s */
> -#define PCI_EXP_LNKCAP2_SLS_5_0GB 0x02 /* Current Link Speed 5.0GT/s */
> -#define PCI_EXP_LNKCAP2_SLS_8_0GB 0x04 /* Current Link Speed 8.0GT/s */
> +#define PCI_EXP_LNKCAP2_SLS_2_5GB 0x02 /* Current Link Speed 2.5GT/s */
> +#define PCI_EXP_LNKCAP2_SLS_5_0GB 0x04 /* Current Link Speed 5.0GT/s */
> +#define PCI_EXP_LNKCAP2_SLS_8_0GB 0x08 /* Current Link Speed 8.0GT/s */
> #define PCI_EXP_LNKCAP2_CROSSLINK 0x100 /* Crosslink supported */
> #define PCI_EXP_LNKCTL2 48 /* Link Control 2 */
> #define PCI_EXP_LNKSTA2 50 /* Link Status 2 */
I think this patch is correct, per spec sec 7.8.18. If I apply it, I
think the comments should also be changed to "Supported Link Speed"
instead of "Current."
The only in-tree user of these symbols is
drm_pcie_get_speed_cap_mask(). Dave, can you ack/nack this? I don't
want to apply this if it's going to break something there.
Bjorn
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