From 67f488dff17e535ac3a8a52b47ff1363d8134983 Mon Sep 17 00:00:00 2001 From: Javier Martinez Canillas Date: Mon, 16 Sep 2024 13:00:26 +0200 Subject: [PATCH] firmware: coreboot: Don't register a pdev if screen_info data is present On coreboot platforms, a system framebuffer may be provided to the Linux kernel by filling a LB_TAG_FRAMEBUFFER entry in the coreboot table. But a coreboot payload (e.g: SeaBIOS) could also provide its own framebuffer information to the Linux kernel. If that's the case, arch x86 boot code will fill the global screen_info data and this used by the Generic System Framebuffers (sysfb) framework, to register a platform device with pdata about the system's framebuffer. But later, the framebuffer_coreboot driver will try to do the same and attempt to register a "simple-framebuffer" platform device (using the information from the coreboot table), which will lead to an error due a device with the same name already being registered: sysfs: cannot create duplicate filename '/bus/platform/devices/simple-framebuffer.0' ... coreboot: could not register framebuffer framebuffer coreboot8: probe with driver framebuffer failed with error -17 To prevent this issue, make the framebuffer_core driver to not register a platform device if the global struct screen_info data has been filled. Reported-by: Brian Norris Closes: https://lore.kernel.org/all/ZuCG-DggNThuF4pj@b20ea791c01f/T/#ma7fb65acbc1a56042258adac910992bb225a20d2 Suggested-by: Julius Werner Signed-off-by: Javier Martinez Canillas Reviewed-by: Thomas Zimmermann Reviewed-by: Brian Norris Reviewed-by: Julius Werner Link: https://lore.kernel.org/r/20240916110040.1688511-3-javierm@redhat.com Signed-off-by: Tzung-Bi Shih --- drivers/firmware/google/framebuffer-coreboot.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/firmware/google/framebuffer-coreboot.c b/drivers/firmware/google/framebuffer-coreboot.c index daadd71d8ddd3..c68c9f56370f2 100644 --- a/drivers/firmware/google/framebuffer-coreboot.c +++ b/drivers/firmware/google/framebuffer-coreboot.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "coreboot_table.h" @@ -36,6 +37,19 @@ static int framebuffer_probe(struct coreboot_device *dev) .format = NULL, }; + /* + * On coreboot systems, the advertised LB_TAG_FRAMEBUFFER entry + * in the coreboot table should only be used if the payload did + * not pass a framebuffer information to the Linux kernel. + * + * If the global screen_info data has been filled, the Generic + * System Framebuffers (sysfb) will already register a platform + * device and pass that screen_info as platform_data to a driver + * that can scan-out using the system provided framebuffer. + */ + if (sysfb_handles_screen_info()) + return -ENODEV; + if (!fb->physical_address) return -ENODEV; -- 2.50.1