[PATCH 6.1.y] drm/amd/display: limit DPIA link rate to HBR3

[PATCH 6.1.y] drm/amd/display: limit DPIA link rate to HBR3

[Mario Limonciello]

From: Peichen Huang <peichen.huang@amd.com>

[Why]
DPIA doesn't support UHBR, driver should not enable UHBR
for dp tunneling

[How]
limit DPIA link rate to HBR3

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Acked-by: Stylon Wang <stylon.wang@amd.com>
Signed-off-by: Peichen Huang <peichen.huang@amd.com>
Reviewed-by: Mustapha Ghaddar <Mustapha.Ghaddar@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 0e69ef6ea82e8eece7d2b2b45a0da9670eaaefff)
This was CC to stable, but failed to apply because the file was
renamed in 6.3-rc1 as part of
54618888d1ea ("drm/amd/display: break down dc_link.c")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
index 5d53e54ebe90..63daf6ecbda7 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1141,6 +1141,11 @@ static bool detect_link_and_local_sink(struct dc_link *link,
 					(link->dpcd_caps.dongle_type !=
 							DISPLAY_DONGLE_DP_HDMI_CONVERTER))
 				converter_disable_audio = true;
+
+			/* limited link rate to HBR3 for DPIA until we implement USB4 V2 */
+			if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA &&
+					link->reported_link_cap.link_rate > LINK_RATE_HIGH3)
+				link->reported_link_cap.link_rate = LINK_RATE_HIGH3;
 			break;
 		}
 
-- 
2.34.1

Re: [PATCH 6.1.y] drm/amd/display: limit DPIA link rate to HBR3

[Greg KH]

On Mon, Aug 07, 2023 at 09:00:47AM -0500, Mario Limonciello wrote:
> From: Peichen Huang <peichen.huang@amd.com>
> 
> [Why]
> DPIA doesn't support UHBR, driver should not enable UHBR
> for dp tunneling
> 
> [How]
> limit DPIA link rate to HBR3
> 
> Cc: Mario Limonciello <mario.limonciello@amd.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: stable@vger.kernel.org
> Acked-by: Stylon Wang <stylon.wang@amd.com>
> Signed-off-by: Peichen Huang <peichen.huang@amd.com>
> Reviewed-by: Mustapha Ghaddar <Mustapha.Ghaddar@amd.com>
> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> (cherry picked from commit 0e69ef6ea82e8eece7d2b2b45a0da9670eaaefff)
> This was CC to stable, but failed to apply because the file was
> renamed in 6.3-rc1 as part of
> 54618888d1ea ("drm/amd/display: break down dc_link.c")

It also is not in 6.4.y, why not?  I can't take it for 6.1.y only,
otherwise people will have a regression when they move to a new kernel.

thanks,

greg k-h

Re: [PATCH 6.1.y] drm/amd/display: limit DPIA link rate to HBR3

[Mario Limonciello]

On 8/9/23 04:05, Greg KH wrote:
> On Mon, Aug 07, 2023 at 09:00:47AM -0500, Mario Limonciello wrote:
>> From: Peichen Huang <peichen.huang@amd.com>
>>
>> [Why]
>> DPIA doesn't support UHBR, driver should not enable UHBR
>> for dp tunneling
>>
>> [How]
>> limit DPIA link rate to HBR3
>>
>> Cc: Mario Limonciello <mario.limonciello@amd.com>
>> Cc: Alex Deucher <alexander.deucher@amd.com>
>> Cc: stable@vger.kernel.org
>> Acked-by: Stylon Wang <stylon.wang@amd.com>
>> Signed-off-by: Peichen Huang <peichen.huang@amd.com>
>> Reviewed-by: Mustapha Ghaddar <Mustapha.Ghaddar@amd.com>
>> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>> (cherry picked from commit 0e69ef6ea82e8eece7d2b2b45a0da9670eaaefff)
>> This was CC to stable, but failed to apply because the file was
>> renamed in 6.3-rc1 as part of
>> 54618888d1ea ("drm/amd/display: break down dc_link.c")
> 
> It also is not in 6.4.y, why not?  I can't take it for 6.1.y only,
> otherwise people will have a regression when they move to a new kernel.
> 
> thanks,
> 
> greg k-h

This is one of those cases that the same commit landed in the tree twice 
as two hashes.

Here's the 6.4 hash (which is identical):

$ git describe --contains 7c5835bcb9176df94683396f1c0e5df6bf5094b3
v6.4-rc7~9^2~2^2

Re: [PATCH 6.1.y] drm/amd/display: limit DPIA link rate to HBR3

[Greg KH]

On Wed, Aug 09, 2023 at 06:18:23AM -0500, Mario Limonciello wrote:
> On 8/9/23 04:05, Greg KH wrote:
> > On Mon, Aug 07, 2023 at 09:00:47AM -0500, Mario Limonciello wrote:
> > > From: Peichen Huang <peichen.huang@amd.com>
> > > 
> > > [Why]
> > > DPIA doesn't support UHBR, driver should not enable UHBR
> > > for dp tunneling
> > > 
> > > [How]
> > > limit DPIA link rate to HBR3
> > > 
> > > Cc: Mario Limonciello <mario.limonciello@amd.com>
> > > Cc: Alex Deucher <alexander.deucher@amd.com>
> > > Cc: stable@vger.kernel.org
> > > Acked-by: Stylon Wang <stylon.wang@amd.com>
> > > Signed-off-by: Peichen Huang <peichen.huang@amd.com>
> > > Reviewed-by: Mustapha Ghaddar <Mustapha.Ghaddar@amd.com>
> > > Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
> > > Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> > > (cherry picked from commit 0e69ef6ea82e8eece7d2b2b45a0da9670eaaefff)
> > > This was CC to stable, but failed to apply because the file was
> > > renamed in 6.3-rc1 as part of
> > > 54618888d1ea ("drm/amd/display: break down dc_link.c")
> > 
> > It also is not in 6.4.y, why not?  I can't take it for 6.1.y only,
> > otherwise people will have a regression when they move to a new kernel.
> > 
> > thanks,
> > 
> > greg k-h
> 
> This is one of those cases that the same commit landed in the tree twice as
> two hashes.
> 
> Here's the 6.4 hash (which is identical):
> 
> $ git describe --contains 7c5835bcb9176df94683396f1c0e5df6bf5094b3
> v6.4-rc7~9^2~2^2

Ah, what a mess, the drm tree never ceases to amaze me...

now queued up, thanks.

greg k-h