On 18.08.2025 16:26, Henrik Grimler wrote: > On Thu, Aug 14, 2025 at 01:26:33PM +0200, Marek Szyprowski wrote: >> On 24.07.2025 20:50, Henrik Grimler wrote: >>> To use MHL we currently need the MHL chip to be permanently on, which >>> consumes unnecessary power. Let's use extcon attached to MUIC to enable >>> the MHL chip only if it detects an MHL cable. >>> >>> Signed-off-by: Henrik Grimler <[email protected]> >>> --- >>> v2: add dependency on extcon. Issue reported by kernel test robot >>> <[email protected]> >>> --- >>> drivers/gpu/drm/bridge/Kconfig | 1 + >>> drivers/gpu/drm/bridge/sii9234.c | 89 >>> ++++++++++++++++++++++++++++++++++++++-- >>> 2 files changed, 87 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig >>> index >>> b9e0ca85226a603a24f90c6879d1499f824060cb..f18a083f6e1c6fe40bde5e65a1548acc61a162ae >>> 100644 >>> --- a/drivers/gpu/drm/bridge/Kconfig >>> +++ b/drivers/gpu/drm/bridge/Kconfig >>> @@ -303,6 +303,7 @@ config DRM_SII902X >>> config DRM_SII9234 >>> tristate "Silicon Image SII9234 HDMI/MHL bridge" >>> depends on OF >>> + select EXTCON >>> help >>> Say Y here if you want support for the MHL interface. >>> It is an I2C driver, that detects connection of MHL bridge >>> diff --git a/drivers/gpu/drm/bridge/sii9234.c >>> b/drivers/gpu/drm/bridge/sii9234.c >>> index >>> 0e0bb1bf71fdcef788715cfd6fa158a6992def33..4d84ba01ea76816bebdbc29d48a041c9c6cd508e >>> 100644 >>> --- a/drivers/gpu/drm/bridge/sii9234.c >>> +++ b/drivers/gpu/drm/bridge/sii9234.c > [ ...] > >>> + >>> + edev = extcon_find_edev_by_node(muic); >>> + of_node_put(muic); >>> + if (IS_ERR(edev)) { >>> + dev_err_probe(ctx->dev, PTR_ERR(edev), >>> + "invalid or missing extcon\n"); >>> + } >> It looks that the original logic got lost somehow in the above code >> block, what causes kernel oops if compiled as module and loaded before >> extcon provider. Please handle -EPROBE_DEFER and propagate error value, >> like the original code did in sii8620 driver: >> >> if (IS_ERR(edev)) { >> if (PTR_ERR(edev) == -EPROBE_DEFER) >> return -EPROBE_DEFER; >> dev_err(ctx->dev, "Invalid or missing extcon\n"); >> return PTR_ERR(edev); >> } > Thanks for detecting the issue! I think my code is just missing return > before dev_err_probe (same mistake as I did on patch 2). With return > added I have not been able to reproduce any kernel oops, but if > CONFIG_DRM_SII9234=y and CONFIG_EXTCON_MAX77693=m then it seems like > linux gets stuck probing sii9234 and waiting for the extcon provider > (verified with some printf debugging). This happens for me both with: > > edev = extcon_find_edev_by_node(muic); > of_node_put(muic); > if (IS_ERR(edev)) { > return dev_err_probe(ctx->dev, PTR_ERR(edev), > "Invalid or missing extcon\n"); > } > > and > > edev = extcon_find_edev_by_node(muic); > of_node_put(muic); > if (IS_ERR(edev)) { > if (PTR_ERR(edev) == -EPROBE_DEFER) > return -EPROBE_DEFER; > dev_err(ctx->dev, "Invalid or missing extcon\n"); > return PTR_ERR(edev); > } > > I am not sure what to do to fix the issue, as far as I can see probe > logic and extcon handling is the same as in sil-sii8620 and ite-it6505 > (i.e. the other bridges that use extcon). Will investigate further.
Indeed your code lacked only the return directive, I've noticed that just after sending my reply. I'm not sure if there is a simple way to solve the endless probe issue with sii9234=y and max77963=m. We have to rely on the user to either keep all drivers compiled-in or configured as modules here. Afair the same issue happens with sii8620 and max77843. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland _______________________________________________ Replicant mailing list [email protected] https://lists.osuosl.org/mailman/listinfo/replicant
