[PATCH net] net: phy: meson-gxl: use MMD access dummy stubs for GXL, internal PHY

[PATCH net] net: phy: meson-gxl: use MMD access dummy stubs for GXL, internal PHY

[Heiner Kallweit]

Jerome provided the information that also the GXL internal PHY doesn't
support MMD register access and EEE. MMD reads return 0xffff, what
results in e.g. completely wrong ethtool --show-eee output.
Therefore use the MMD dummy stubs.

Note: The Fixes tag references the commit that added the MMD dummy
access stubs.

Fixes: 5df7af85ecd8 ("net: phy: Add general dummy stubs for MMD register access")
Suggested-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/net/phy/meson-gxl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/phy/meson-gxl.c b/drivers/net/phy/meson-gxl.c
index c49062ad7..fbf5f2416 100644
--- a/drivers/net/phy/meson-gxl.c
+++ b/drivers/net/phy/meson-gxl.c
@@ -261,6 +261,8 @@ static struct phy_driver meson_gxl_phy[] = {
 		.handle_interrupt = meson_gxl_handle_interrupt,
 		.suspend        = genphy_suspend,
 		.resume         = genphy_resume,
+		.read_mmd	= genphy_read_mmd_unsupported,
+		.write_mmd	= genphy_write_mmd_unsupported,
 	}, {
 		PHY_ID_MATCH_EXACT(0x01803301),
 		.name		= "Meson G12A Internal PHY",
-- 
2.39.1

Re: [PATCH net] net: phy: meson-gxl: use MMD access dummy stubs for GXL, internal PHY

[Chris Healy]

Reviewed-by: Chris Healy <healych@amazon.com>

On Tue, Jan 31, 2023 at 1:03 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>
> Jerome provided the information that also the GXL internal PHY doesn't
> support MMD register access and EEE. MMD reads return 0xffff, what
> results in e.g. completely wrong ethtool --show-eee output.
> Therefore use the MMD dummy stubs.
>
> Note: The Fixes tag references the commit that added the MMD dummy
> access stubs.
>
> Fixes: 5df7af85ecd8 ("net: phy: Add general dummy stubs for MMD register access")
> Suggested-by: Jerome Brunet <jbrunet@baylibre.com>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
>  drivers/net/phy/meson-gxl.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/phy/meson-gxl.c b/drivers/net/phy/meson-gxl.c
> index c49062ad7..fbf5f2416 100644
> --- a/drivers/net/phy/meson-gxl.c
> +++ b/drivers/net/phy/meson-gxl.c
> @@ -261,6 +261,8 @@ static struct phy_driver meson_gxl_phy[] = {
>                 .handle_interrupt = meson_gxl_handle_interrupt,
>                 .suspend        = genphy_suspend,
>                 .resume         = genphy_resume,
> +               .read_mmd       = genphy_read_mmd_unsupported,
> +               .write_mmd      = genphy_write_mmd_unsupported,
>         }, {
>                 PHY_ID_MATCH_EXACT(0x01803301),
>                 .name           = "Meson G12A Internal PHY",
> --
> 2.39.1
>

Re: [PATCH net] net: phy: meson-gxl: use MMD access dummy stubs for GXL, internal PHY

[Jakub Kicinski]

On Tue, 31 Jan 2023 22:03:21 +0100 Heiner Kallweit wrote:
> Jerome provided the information that also the GXL internal PHY doesn't
> support MMD register access and EEE. MMD reads return 0xffff, what
> results in e.g. completely wrong ethtool --show-eee output.
> Therefore use the MMD dummy stubs.
> 
> Note: The Fixes tag references the commit that added the MMD dummy
> access stubs.
> 
> Fixes: 5df7af85ecd8 ("net: phy: Add general dummy stubs for MMD register access")

Please make sure to CC the author. Adding Kevin Hao <haokexin@gmail.com>

Re: [PATCH net] net: phy: meson-gxl: use MMD access dummy stubs for GXL, internal PHY

[Kevin Hao]

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On Tue, Jan 31, 2023 at 09:55:28PM -0800, Jakub Kicinski wrote:
> On Tue, 31 Jan 2023 22:03:21 +0100 Heiner Kallweit wrote:
> > Jerome provided the information that also the GXL internal PHY doesn't
> > support MMD register access and EEE. MMD reads return 0xffff, what
> > results in e.g. completely wrong ethtool --show-eee output.
> > Therefore use the MMD dummy stubs.
> > 
> > Note: The Fixes tag references the commit that added the MMD dummy
> > access stubs.
> > 
> > Fixes: 5df7af85ecd8 ("net: phy: Add general dummy stubs for MMD register access")
> 
> Please make sure to CC the author. Adding Kevin Hao <haokexin@gmail.com>

The changes look fine to me, but the using of the "Fixes" tag seems a bit weird.
The "Fixes" tag is used to specify the commit causing regression instead of patch prerequisite.

Thanks,
Kevin


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Re: [PATCH net] net: phy: meson-gxl: use MMD access dummy stubs for GXL, internal PHY

[Heiner Kallweit]

On 02.02.2023 06:07, Jakub Kicinski wrote:
> On Wed, 1 Feb 2023 20:45:58 +0800 Kevin Hao wrote:
>> The "Fixes" tag is used to specify the commit causing regression
>> instead of patch prerequisite.
> 
> Indeed, what's the tag for the commit where the problem can be first
> observed? All the way back to:
> 
> Fixes: 7334b3e47aee ("net: phy: Add Meson GXL Internal PHY driver")
> 
> ?

The issue popped up with:
d853d145ea3e ("net: phy: add an option to disable EEE advertisement")

This commit added MMD register access to the generic configuration
path in phylib.

Re: [PATCH net] net: phy: meson-gxl: use MMD access dummy stubs for GXL, internal PHY

[Paolo Abeni]

On Thu, 2023-02-02 at 07:30 +0100, Heiner Kallweit wrote:
> On 02.02.2023 06:07, Jakub Kicinski wrote:
> > On Wed, 1 Feb 2023 20:45:58 +0800 Kevin Hao wrote:
> > > The "Fixes" tag is used to specify the commit causing regression
> > > instead of patch prerequisite.
> > 
> > Indeed, what's the tag for the commit where the problem can be first
> > observed? All the way back to:
> > 
> > Fixes: 7334b3e47aee ("net: phy: Add Meson GXL Internal PHY driver")
> > 
> > ?
> 
> The issue popped up with:
> d853d145ea3e ("net: phy: add an option to disable EEE advertisement")
> 
> This commit added MMD register access to the generic configuration
> path in phylib.

Please post a v2 with an update Fixes tag, and ev, referencing the pre-
requisite  in the the commit message itself, thanks!

Paolo

Re: [PATCH net] net: phy: meson-gxl: use MMD access dummy stubs for GXL, internal PHY

[Chris Healy]

On Tue, Jan 31, 2023 at 9:55 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Tue, 31 Jan 2023 22:03:21 +0100 Heiner Kallweit wrote:
> > Jerome provided the information that also the GXL internal PHY doesn't
> > support MMD register access and EEE. MMD reads return 0xffff, what
> > results in e.g. completely wrong ethtool --show-eee output.
> > Therefore use the MMD dummy stubs.
> >
> > Note: The Fixes tag references the commit that added the MMD dummy
> > access stubs.
> >
> > Fixes: 5df7af85ecd8 ("net: phy: Add general dummy stubs for MMD register access")
>
> Please make sure to CC the author. Adding Kevin Hao <haokexin@gmail.com>

Good point, I'll do that next time.