Hi, > 2026年8月3日 21:45，Huacai Chen <[email protected]> 写道： > > On Fri, Jul 31, 2026 at 4:24 PM Miao Wang <[email protected]> wrote: >> >> Hi, >> >>> 2026年7月31日 16:07，Huacai Chen <[email protected]> 写道： >>> >>> On Fri, Jul 24, 2026 at 5:28 PM Miao Wang <[email protected]> wrote: >>>> >>>> Hi, >>>> >>>>> 2026年7月24日 16:55，Huacai Chen <[email protected]> 写道： >>>>> >>>>> Hi, Miao, >>>>> >>>>> On Fri, Jul 10, 2026 at 1:24 AM Miao Wang via B4 Relay >>>>> <[email protected]> wrote: >>>>>> >>>>>> Previously, the driver has been introduced to support the Loongson 2K >>>>>> BMC running on the Loongson Servers, which is essential to prevent >>>>>> the system from hanging when the BMC is being reset and the default >>>>>> efi-framebuffer is being used. However, there are some drawbacks in the >>>>>> driver. >>>>>> >>>>>> Firstly, the driver tries to read and write to the connected PCI-E host >>>>>> controller registers, assuming that the BMC is connected to LS7A PCI-E >>>>>> host controller. This assumption should be true for real products, but >>>>>> to prevent from accidentally reading and writing to the wrong PCI-E host >>>>>> controller, this driver should be modified to check this before >>>>>> accessing the registers. >>>>>> >>>>>> Secondly, the driver uses non-exported functions to tell the vt >>>>>> subsystem to redraw the screen, preventing the driver from being >>>>>> compiling as a module. This can be fixed by using the exported >>>>>> functions instead. >>>>> You can replace the redraw function, but I don't think it is necessary >>>>> to make the bmc driver modular. >>>>> >>>>> BMC core, IPMI and simpledrm display are usually (if not always) >>>>> supposed to work as early as possible. >>>> >>>> I believe that it should be the user's decision to choose whether to >>>> compile a module into the kernel or as a module and it would be better >>>> if we can provide the possibilities for the user to choose from. >>>> Additionally, I don't think these modules are supposed to work that >>>> early. The mfd module provide two functions, the display and the ipmi >>>> device. In the aspect of graphical display, without this module, the >>>> user can still see the output during booting on their monitors, since >>>> efifb is working, providing a basic display function. In the aspect of >>>> the ipmi device, I don't think the lack of such device will influence >>>> the boot of the system, since it is a common practice to compile ipmi >>>> device drivers as modules on other architectures. As a result, neither >>>> of the two functions are required to be loaded that early and it is >>>> reasonable to at lease leave the choice to compile it as a module >>>> to the user. >>> Flexibility is not always useful, if a config doesn't provide good >>> effect, then it just increases complexity and makes maintenance more >>> difficult. >> >> I should emphasize that to allow this driver to be a module, there is >> no such increase on maintenance. Moreover, not all loongarch machines >> are requiring this driver. Especially only a part of the server models >> are quipped with this BMC. Comparing with other architectures, the >> driver for BMC are normally compiled as a module, such as mgag200 for >> iLO from HPE and iDRAC from DELL, hibmc_drm for Kunpeng server from >> Huawei. None of these BMC drivers requiring to be compiled into the >> kernel. I cannot see there is any reason keeping the driver from being >> allowed to be compiled as a module. I also do not think it will bring >> any significant maintenance burden. Implementing correct cleanup code >> should be necessary instead of burden. > Can we split into two series, one fix bugs and the others make bmc modular? > > Otherwise I don't think we can reach a consensus in the near future.
I accept different opinions on design trade-offs. However, I don't think you have provided enough excuses to remain this driver as built-in, since I believe normally in kernel, most non-core drivers are all able to be compiled as a module. I also provided some examples from devices with similar functions. As a result, I'll not split this series before there is indeed a strong reason against allowing this driver to be compiled as a module or we may have a great benefit if we force this module to be compiled built-in. Cheers, Miao Wang _______________________________________________ Openipmi-developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/openipmi-developer
