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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Authority-Analysis: v=2.4 cv=VefH+lp9 c=1 sm=1 tr=0 ts=6a1021c6 cx=c_pps a=HLyN3IcIa5EE8TELMZ618Q==:117 a=PRfkaYvzSr8QmIIGAkY2Sg==:17 a=IkcTkHD0fZMA:10 a=NGcC8JguVDcA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=yOCtJkima9RkubShWh1s:22 a=pGLkceISAAAA:8 a=wrdFt3MdCHdAHujQ4X4A:9 a=QEXdDO2ut3YA:10 a=bTQJ7kPSJx9SKPbeHEYW:22 X-Proofpoint-GUID: KuMfuR0aIcXdW-48k8jifu94vxY82YCz X-Proofpoint-ORIG-GUID: KuMfuR0aIcXdW-48k8jifu94vxY82YCz X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTIyMDA5MyBTYWx0ZWRfXw6XUCkR7QDLf DQJjHWMucq05+I5S2NJxRaNT8UwF27H4qVQRpRkJyKSTCxTjSwBBTPpFjLv9pbatrhOeXCMw6AD vrKjK/R53JXMjLI+Rb6hJMzaNtCfSx4H9uyhBGCMlZTchv2nxZyPPu92z4gloIUkLnksuRSZ16O 3G3eT2n38UIFGiuerqUuJGVgqt1Cq/9cdOZPy1C4HI2jj26uhsNX7jJmY2jgOYYu5+4QtoMtZiI OeLbUcNJJ1j58vavvcbRvSOR9rm381QhJjyJmJw36Tg6oSr8zB2NgjtQuEVqNwvnJ4QGq25AmvV NOxLp4ioOXyiD8DAd+n0cH29q/YreJkGkhFLlPVYXcwCQOiXnUPBZd6Y4j+epvswqRUoS1amcGR yftiVALsegDOC1sOh11MM1a37oY3Dj1KGGMT6qvMkD5AOtC60e5OT79w5xW/rxNUzpa+S3WeOtP IxSJKgdAMUiaQfqKUKQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-05-22_02,2026-05-18_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 phishscore=0 lowpriorityscore=0 clxscore=1015 priorityscore=1501 bulkscore=0 spamscore=0 malwarescore=0 adultscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605130000 definitions=main-2605220093 On 5/22/26 8:06 AM, Graham O'Connor wrote: > The RA620 DP-to-HDMI bridge used on the Radxa Dragon Q6A does not > acknowledge DP link training at voltage swing level 3. The bridge > requests maximum voltage swing but never completes link training > when the driver attempts level 3, causing HDMI output to fail. > > Cap DP_TRAIN_LEVEL_MAX at 2 to match the behaviour of the vendor > kernel, where link training completes successfully at level 2. > This allows the RA620 bridge to establish a stable HDMI connection. > > Tested on Radxa Dragon Q6A (QCS6490) with RA620 DP-to-HDMI bridge > > Signed-off-by: Graham O'Connor > --- > drivers/gpu/drm/msm/dp/dp_link.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_link.h b/drivers/gpu/drm/msm/dp/dp_link.h > index 76125e9c0..ff0d8e99d 100644 > --- a/drivers/gpu/drm/msm/dp/dp_link.h > +++ b/drivers/gpu/drm/msm/dp/dp_link.h > @@ -24,7 +24,7 @@ struct msm_dp_link_info { > unsigned long capabilities; > }; > > -#define DP_TRAIN_LEVEL_MAX 3 > +#define DP_TRAIN_LEVEL_MAX 2 You're limiting this value for *all* devices featuring a Qualcomm SoC with a DP controller. Instead, if this is really an issue that results from the bridge's capabilities (which could potentially only be a symptom, not the cause), this should be somehow limited to the specific bridge itself Konrad