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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?dBMeC6ZOfDPdN1D9kWHIgnqQSicklpylBjRfpfJdC3DINgmjrc3gs3w9MKFC?= =?us-ascii?Q?NcGACCy00pYMQKpYcazSWaHNE5MKGntzUtm5tBB3kA1rjM66tva4ygNNLVo5?= =?us-ascii?Q?EswoalMn9090yDQESWjZorDYuw+usmCooVKYuow7ce2FIRYdcMzmBPMg0jVd?= =?us-ascii?Q?+h1BliwIuyBRKSTUQ1pgiIwg3CrsUVlkaVVF7qMiHI5GAztLQNjTz73so1ay?= =?us-ascii?Q?YrpsR2n9oDDwG5BppDB/QkXrZgxjQAm4Cu33Tj+khB1XNnlgus2vzQsDoQRX?= =?us-ascii?Q?juH9ni79xrdMR6b1qmAFFHjlQbjS+Z/UAYIVQeF47YzLDfVdyf53v4ubthvH?= =?us-ascii?Q?cUvkVwxShTRIMuA++BlcXZfpsNdTp+FN4mqBWLQtpGN+ZgF6RG6kRpXI+mWJ?= =?us-ascii?Q?wrBjRp3fjRsCqYX25d9AQUSlwV1oI+eTf6s/PYcd2uWBZJB1TaJsowW69+6x?= =?us-ascii?Q?xErB01c0uKc5qIBNAdHZuO9Utobuht/iZ7oCUV9C0zrMoiiVwWxyXANdTkms?= =?us-ascii?Q?rtYk1tsKluw3u3f9iWedXq4hTmtJrGqxflzurMZSHJeN+t71nYf6mSpV8BCR?= =?us-ascii?Q?mtFWv2kwliwx6iMC/V2Bdk5aUwDWGIhmOrEsrqTuY4IUevFiinbZY7tYJEJa?= =?us-ascii?Q?50ct+v+KaWLseP3V+u2z32jQ5EcTfFm2jyfmLE4PuF7FUWiMV/nlGAM0+gbY?= =?us-ascii?Q?fnktyrI/rZNT1s9Jox0pbtDO4pyfN4HTeTnJCfnIpQABlFITvC6KMmotD0TF?= =?us-ascii?Q?8tjmb6dKxrII3Bj3shD21WJ5M9LDXf8tbhj7PHIju7JhQnJ0VTOJBPpBQeob?= =?us-ascii?Q?y5/bkllHAIs5wHjMIW6a5e5Kohgn4CPkHdQeNJdcqnXVHUnf0T5CnVstxo9e?= =?us-ascii?Q?CUd2JjRVST4EHHbZX8CE/ZSNyc2u4wKGxYRobdZyR7A5Kx3HjwZswie7JSGU?= =?us-ascii?Q?tkQxtn1wTVZRtzC5Xm5FvNzNvYtFCOdz0AvNC0nb1tfKZ6aA6IIrzwxkdrcM?= =?us-ascii?Q?78ZXbKIxQrUlRuHEL1yE3bUL7dim/XgCDfvF3+Bp8gkCRKZgoIm6xKC0vEdj?= =?us-ascii?Q?61nq5gm1+GgzteGBOdcldZTtijOgV+BCXmCdRbFhfvWeoYdnUX707j6+QlFd?= =?us-ascii?Q?/eGXW/VSg6p+vbLS80Yzh5kkNGYUYeuk37Tqypgn6i5P3N3pFM05Q9eT/4G1?= =?us-ascii?Q?1QWEkpp61SRlRp7rt06o/esO7Or1sVSQf4dg9NmDs4U/iDzQeFhqVyGk6VsJ?= =?us-ascii?Q?KUijysg8Lw6PFgIvB8//WQ5Yg2JC605vf+QQkjHshTE+t40iWxqSmiwA/X9j?= =?us-ascii?Q?y7mnQX8zisy4ERJPpS0z0a3uXzHR08qfT8vf54FjcaISsq2oJYxZ5Krb8rHk?= =?us-ascii?Q?ACX+akGqfGkfvtVjel14tL23PanYwhieqiP2owYA1mjB6pnuZqAWeP+bgdxi?= =?us-ascii?Q?gkbTSnUMDezrQuIvcVEQK5y8TRqS4FgL/4lF1p4xnd8FK86gAlTjn/ACNdgt?= =?us-ascii?Q?SFAbJArxW+z0e8QA+ZPqv3QJiPcdGsBA3LvBfq7IcwGg05J/oZPYGdwjMp7M?= =?us-ascii?Q?B6bffp7F2d7AYkPPeAhNno9lkmibsbvQ2UBTD9g1bCiL3ZmIdudl/qRfuqTZ?= =?us-ascii?Q?pZcH4iCUr6hGwsR2TOmCckQ=3D?= X-OriginatorOrg: vpitech.com X-MS-Exchange-CrossTenant-Network-Message-Id: 33001fe2-ee0b-461c-266f-08d9db75c953 X-MS-Exchange-CrossTenant-AuthSource: CO1P222MB0212.NAMP222.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Jan 2022 18:01:58.7942 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 130d6264-38b7-4474-a9bf-511ff1224fac X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: H0skyJwDGkLPVDXPzpj3TTh0YvcObrzTs5xeOP7wAiOlfF4EARM8pQ07v+Aru1kQruArmYihfmxC8xDrQamE8A== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0P222MB0465 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On Thu, 20 Jan 2022 02:32:02 +0900 Hector Martin wrote: > On 20/01/2022 01.49, Alex Henrie wrote: > > I think Hector's patch to share the SMBus is a great idea; my patch was > > meant to complement his, not replace it. The problem is that when I > > tried Hector's patch, I got the message "BIOS left SMBus locked". So I > > didn't want to let the BIOS touch the SMBus at all because once it had > > the lock, it seemed to never let go. However, today I tried v2 of > > Hector's patch [1] instead of v3 [2], and v2 worked perfectly! My guess > > is that despite the text of the error message, it's Linux that's > > leaving the SMBus locked, not the BIOS. > > > > The only difference between v2 and v3 is that v2 called > > outb_p(SMBHSTSTS_INUSE_STS, SMBHSTSTS(priv)) at the end of i801_access. > > Hector, can you clarify why you removed that call in v3? > > Well that solves the mystery. > > That line was split off and submitted separately in another patch, as it > fixes the immediate breakage that I was trying to address with my patch, > namely that *linux* left the SMBus locked and that broke BIOS accesses. > The full patch implements proper sharing logic; that line alone is > enough to unbork the backlight on iMacs (among other things) which was > the immediate regression I had encountered. The rest of the patch breaks > horribly without that line, as you'd expect, since it's trying to work > around a broken BIOS when Linux itself is broken. > > That patch was posted in June 2021 and CC'd stable [1], and was merged > into the stable 5.10 and 5.12 trees as well as released in 5.13. So, you > must be running an old kernel :-). > > [1] > https://lore.kernel.org/linux-i2c/cefbeb76-5f7f-036b-fa0e-1e339d261c35@gmail.com/ Excellent! Thank you so much Hector. Indeed, this system is currently using a custom-built 5.4 kernel. Jean, please feel free to disregard my patch and to commit Hector's with "Tested-by: Alex Henrie ". -Alex