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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-GUID: ZlaDGGp9iIcW20WVYDalXkG0E1eaocB_ X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTAzMDEyNyBTYWx0ZWRfX5Z5lWmuiU41k ShuAvCELAKDWMTsaxvQt53e4Cyl1bcvmefO5x//JvxWyyGVXgZpkChNBhb3iUsy1IpTdE4QSnwA HllSYnqYGHEqE/jiM+rI95bdPSAB2fzeHW+lmqFYQxnx3xYv5TpLvWGCDp3PT3WYHuc/RUg/XMB dBwG8qLAy+qipqJ6k19VsJiW5RgnO+X2DsNL5uoqQ1Unv40tj6BNJQosWmpZCueqkg3AUdiYSrj YXuakhugqnAAQzkYFqQCJNiCXwbd2AUSVx9lhL0H2Yi7sNurK1+wmJUGHkm73I0bBL/uxaDy/H3 LieowybGz/TJmBfMHKmeCPLN5XbxLe2luuYKzQM0n3sZaRuhWSReiF5wAd/q4rFiDlgbEIVYUOG xmiCkSf0NmXqfdD4VLkvq8HSHaPVkxzNGBxLgYm8ze90ad14jXbExScxU3Z0PJItnNNiXa9R04m HvYfpe5RN6JCpFXNmAA== X-Authority-Analysis: v=2.4 cv=X8Ji7mTe c=1 sm=1 tr=0 ts=6a9986f5 cx=c_pps a=P2rfLEam3zuxRRdjJWA2cw==:117 a=PRfkaYvzSr8QmIIGAkY2Sg==:17 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=_K5XuSEh1TEqbUxoQ0s3:22 a=z2R-DqfiRA8ArFDFZ6YA:9 a=QEXdDO2ut3YA:10 a=ODZdjJIeia2B_SHc_B0f:22 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTAzMDEyNyBTYWx0ZWRfX9KWM2KuM+aJ2 nmKb80purVj/9+5r42AbGtj8DasADSM7h0xyilAxcFGCSIMus8yRmNnkkZv+ubR7iV+jw7jcFHb PEjF8MMLOULVbjkZ86zQV8q+bKsSZzU= X-Proofpoint-ORIG-GUID: ZlaDGGp9iIcW20WVYDalXkG0E1eaocB_ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-03_04,2026-09-03_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 spamscore=0 phishscore=0 lowpriorityscore=0 impostorscore=0 priorityscore=1501 adultscore=0 bulkscore=0 clxscore=1015 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609030127 On 9/2/26 11:31 AM, Xilin Wu wrote: > On 9/2/2026 4:43 PM, Konrad Dybcio wrote: >> On 9/1/26 10:47 AM, Xilin Wu wrote: >>> The TC9563 PCI power-control driver powers off external downstream ports >>> whose device tree nodes have status = "disabled". >>> >>> On the Radxa Dragon Q8B, reading the Vendor ID from one of these >>> powered-off port functions during PCI enumeration raises an Arm SError >>> instead of returning an all-ones PCI error response. This prevents the >>> board from completing boot. >> >> I agree with the premise of the patch, but I'd like to understand why >> that happens - do you have any details? > > Unfortunately, I don't have further details. The downstream kernel also includes a similar workaround, so I suspect it's related to how the TC9563 chip is designed. I'm curious in why the port is still advertised on the bus if the i2c interface writes some magic bits to "disable" it on the IC side.. but perhaps that's just how that IC behaves and we can't do anything about it? Konrad