| Message ID | 20200220123012.19179-1-m.szyprowski@samsung.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | drm/exynos: dsi: fix workaround for the legacy clock name | expand |
On 20.02.2020 13:30, Marek Szyprowski wrote: > Writing to the built-in strings arrays doesn't work if driver is loaded > as kernel module. This is also considered as a bad pattern. Fix this by > adding a call to clk_get() with legacy clock name. This fixes following > kernel oops if driver is loaded as module: > > Unable to handle kernel paging request at virtual address bf047978 > pgd = (ptrval) > [bf047978] *pgd=59344811, *pte=5903c6df, *ppte=5903c65f > Internal error: Oops: 80f [#1] SMP ARM > Modules linked in: mc exynosdrm(+) analogix_dp rtc_s3c exynos_ppmu i2c_gpio > CPU: 1 PID: 212 Comm: systemd-udevd Not tainted 5.6.0-rc2-next-20200219 #326 > videodev: Linux video capture interface: v2.00 > Hardware name: Samsung Exynos (Flattened Device Tree) > PC is at exynos_dsi_probe+0x1f0/0x384 [exynosdrm] > LR is at exynos_dsi_probe+0x1dc/0x384 [exynosdrm] > ... > Process systemd-udevd (pid: 212, stack limit = 0x(ptrval)) > ... > [<bf03cf14>] (exynos_dsi_probe [exynosdrm]) from [<c09b1ca0>] (platform_drv_probe+0x6c/0xa4) > [<c09b1ca0>] (platform_drv_probe) from [<c09afcb8>] (really_probe+0x210/0x350) > [<c09afcb8>] (really_probe) from [<c09aff74>] (driver_probe_device+0x60/0x1a0) > [<c09aff74>] (driver_probe_device) from [<c09b0254>] (device_driver_attach+0x58/0x60) > [<c09b0254>] (device_driver_attach) from [<c09b02dc>] (__driver_attach+0x80/0xbc) > [<c09b02dc>] (__driver_attach) from [<c09ade00>] (bus_for_each_dev+0x68/0xb4) > [<c09ade00>] (bus_for_each_dev) from [<c09aefd8>] (bus_add_driver+0x130/0x1e8) > [<c09aefd8>] (bus_add_driver) from [<c09b0d64>] (driver_register+0x78/0x110) > [<c09b0d64>] (driver_register) from [<bf038558>] (exynos_drm_init+0xe8/0x11c [exynosdrm]) > [<bf038558>] (exynos_drm_init [exynosdrm]) from [<c0302fa8>] (do_one_initcall+0x50/0x220) > [<c0302fa8>] (do_one_initcall) from [<c03dd02c>] (do_init_module+0x60/0x210) > [<c03dd02c>] (do_init_module) from [<c03dbf44>] (load_module+0x1c0c/0x2310) > [<c03dbf44>] (load_module) from [<c03dc85c>] (sys_finit_module+0xac/0xbc) > [<c03dc85c>] (sys_finit_module) from [<c0301000>] (ret_fast_syscall+0x0/0x54) > Exception stack(0xd979bfa8 to 0xd979bff0) > ... > ---[ end trace db16efe05faab470 ]--- > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Why did it worked with build-in driver remains mystery. Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> -- Regards Andrzej > --- > drivers/gpu/drm/exynos/exynos_drm_dsi.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c > index 33628d85edad..08a8ce3f499c 100644 > --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c > +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c > @@ -1787,9 +1787,10 @@ static int exynos_dsi_probe(struct platform_device *pdev) > dsi->clks[i] = devm_clk_get(dev, clk_names[i]); > if (IS_ERR(dsi->clks[i])) { > if (strcmp(clk_names[i], "sclk_mipi") == 0) { > - strcpy(clk_names[i], OLD_SCLK_MIPI_CLK_NAME); > - i--; > - continue; > + dsi->clks[i] = devm_clk_get(dev, > + OLD_SCLK_MIPI_CLK_NAME); > + if (!IS_ERR(dsi->clks[i])) > + continue; > } > > dev_info(dev, "failed to get the clock: %s\n",
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c index 33628d85edad..08a8ce3f499c 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c @@ -1787,9 +1787,10 @@ static int exynos_dsi_probe(struct platform_device *pdev) dsi->clks[i] = devm_clk_get(dev, clk_names[i]); if (IS_ERR(dsi->clks[i])) { if (strcmp(clk_names[i], "sclk_mipi") == 0) { - strcpy(clk_names[i], OLD_SCLK_MIPI_CLK_NAME); - i--; - continue; + dsi->clks[i] = devm_clk_get(dev, + OLD_SCLK_MIPI_CLK_NAME); + if (!IS_ERR(dsi->clks[i])) + continue; } dev_info(dev, "failed to get the clock: %s\n",
Writing to the built-in strings arrays doesn't work if driver is loaded as kernel module. This is also considered as a bad pattern. Fix this by adding a call to clk_get() with legacy clock name. This fixes following kernel oops if driver is loaded as module: Unable to handle kernel paging request at virtual address bf047978 pgd = (ptrval) [bf047978] *pgd=59344811, *pte=5903c6df, *ppte=5903c65f Internal error: Oops: 80f [#1] SMP ARM Modules linked in: mc exynosdrm(+) analogix_dp rtc_s3c exynos_ppmu i2c_gpio CPU: 1 PID: 212 Comm: systemd-udevd Not tainted 5.6.0-rc2-next-20200219 #326 videodev: Linux video capture interface: v2.00 Hardware name: Samsung Exynos (Flattened Device Tree) PC is at exynos_dsi_probe+0x1f0/0x384 [exynosdrm] LR is at exynos_dsi_probe+0x1dc/0x384 [exynosdrm] ... Process systemd-udevd (pid: 212, stack limit = 0x(ptrval)) ... [<bf03cf14>] (exynos_dsi_probe [exynosdrm]) from [<c09b1ca0>] (platform_drv_probe+0x6c/0xa4) [<c09b1ca0>] (platform_drv_probe) from [<c09afcb8>] (really_probe+0x210/0x350) [<c09afcb8>] (really_probe) from [<c09aff74>] (driver_probe_device+0x60/0x1a0) [<c09aff74>] (driver_probe_device) from [<c09b0254>] (device_driver_attach+0x58/0x60) [<c09b0254>] (device_driver_attach) from [<c09b02dc>] (__driver_attach+0x80/0xbc) [<c09b02dc>] (__driver_attach) from [<c09ade00>] (bus_for_each_dev+0x68/0xb4) [<c09ade00>] (bus_for_each_dev) from [<c09aefd8>] (bus_add_driver+0x130/0x1e8) [<c09aefd8>] (bus_add_driver) from [<c09b0d64>] (driver_register+0x78/0x110) [<c09b0d64>] (driver_register) from [<bf038558>] (exynos_drm_init+0xe8/0x11c [exynosdrm]) [<bf038558>] (exynos_drm_init [exynosdrm]) from [<c0302fa8>] (do_one_initcall+0x50/0x220) [<c0302fa8>] (do_one_initcall) from [<c03dd02c>] (do_init_module+0x60/0x210) [<c03dd02c>] (do_init_module) from [<c03dbf44>] (load_module+0x1c0c/0x2310) [<c03dbf44>] (load_module) from [<c03dc85c>] (sys_finit_module+0xac/0xbc) [<c03dc85c>] (sys_finit_module) from [<c0301000>] (ret_fast_syscall+0x0/0x54) Exception stack(0xd979bfa8 to 0xd979bff0) ... ---[ end trace db16efe05faab470 ]--- Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- drivers/gpu/drm/exynos/exynos_drm_dsi.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)